Rearend size - some like'm big - some like'm small - your o-pinion?

[Daytona Guy]

My Hemi has 713 HP and 750 trq @ 4g and I want to drive this car on long trips. I have 3.23's in my yellow Daytona and freeway driving at 75 mph seems to wind the thing up too high for that long. I was thinking with 2.94's in my new blue Daytona with this trq it will have no problem moving off the start, even lighting it up, and driving at a cruse altitude of 75 mph @ 2800-3000 rpm's would make for a more enjoyable trip.

Rearend size - some like'm big - some like'm small - your o-pinion?

Dane

[cdr]

overdrive 

[JB400]

Looks like you're gonna have to keep them small if you want to drive them.  I don't see gas prices getting any cheaper now.

[ODZKing]

I will never take them to the track but we do take trips.
2.94 in the 67(383) and 2.71 in the 73(400hp)

[Daytona Guy]

overdrive 

Agreed, but ridiculously expensive.   

Dane

[Daytona Guy]

I will never take them to the track but we do take trips.
2.94 in the 67(383) and 2.71 in the 73(400hp)

With your 2.94's @ 65 mph what is your rpm's. My rpm's can't be too low for my cam .557/.526 -- .235/.249 @ 50 (converter will be 2300-2500).

Dane

[ODZKing]

I will never take them to the track but we do take trips.
2.94 in the 67(383) and 2.71 in the 73(400hp)

With your 2.94's @ 65 mph what is your rpm's. My rpm's can't be too low for my cam .557/.526 -- .235/.249 @ 50 (converter will be 2300-2500).

Dane

As I recall 55 was just under 2000.  65 I want to say 2200 or so.  Right around there.
I get 17-18 mpg with the 67 on trips.  For a 383 4bbl - I think that is OK.

[cdr]

overdrive 

Agreed, but ridiculously expensive.   

Dane

its not that bad cost when going to a518 trans. i have about 1200.00 for everything,still gotta build a cross member

[cdr]

unless you already had your 727 built, it cost me about 300.00 more to do the 518 over doing a 727

[Dino]

I have 2:96 with near 26" tires and it's pretty good on the highway, not all that high in rpm but I couldn't tell you how much it is.  The 727 needs to go though, I need more gears.  It's very easy to light em up with these gears but I only have 225 wide tires.  I had 3:55 before which makes it much quicker off the line but anything above 45 mph was just too annoying.

[Mike DC]

                
Overdrives are ridiculously expensive but 700hp Hemis are ridiculously expensive too.   I can't see that motor happening for less than 5 figures.

Dropping a couple grand on a nice overdrive setup to enjoy it better and make it last longer . . . not a bad deal in the big picture IMHO.  



IMHO even an overdrive setup could still use relatively tall axle gears, especially with a modern tranny that has a low 1st gear.  Seriously, what good is a 1st gear ratio low enough to spin 5000 rpm at walking speed?  It's worthless for anything other than tearing the tires off the back wheels, and you can still do that with higher gearing when you've got so much motor.  

Meanwhile I think it really makes a difference when you can get the cruise RPM down low on the freeway.  If big engines & tall gear ratios cost nothing then we would all want to have the option of going down to 1500rpm @ 75 mph.

[Cooter]

overdrive 

Agreed, but ridiculously expensive.   

Dane

Did I read this correctly??? You have a 713 HP HEMI, clearly by the standards of the board here in the 5-speed from Passion Perf., you should be able to afford a newer 5-speed easily....Yet, you say they are rediculously expensive...

[Daytona Guy]

When you reach your limit - you reach your limit. The overdrive and all the electrical lockup - and cost and hastle I just want a happy medium - cant stand manuals they drive like a truck. Plus when I'm driving down the freeway and want to get on it - tall (high) gears just go nowhere - I want to leave the fart cars in the dust

Money is always an issue on any build - Hemi or not. Without a lid cars sit in a gaurage for years waiting for that next part they can't afford.

Dane

[Dino]

Although not the fastest, with my combo I have no problem going from 70-100 in very little time.  Torque will do that.  On the rural roads here the limit is 55, with my daily I pass one car at a time, with the Charger 3 or 4 in less time.  Torque is my friend.    

The a518 would have been a nice option for you Dane but your hemi might tear that thing up.

[Mike DC]

           
Yeah, if I had 700 hp then I wouldn't compromise the gearing to make it any faster.  Just gear it tall for cruising and let the engine do the work when you wanna go fast. 

[Daytona Guy]

So 3.23's or 2.94's

Does anyone know a formula? Tire size, gears, 1 to 1 3rd gear trany, RPM = Speed? There has to be...

Dane

[Dino]

So 3.23's or 2.94's

Does anyone know a formula? Tire size, gears, 1 to 1 3rd gear trany, RPM = Speed? There has to be...

Dane

This may help:

http://vexer.com/automotive-tools/speed-rpm-calculator

[JB400]

I'm with Cooter on this one.  If you can afford a 700hp+ engine, you can afford to put a 5-6 speed gear banger behind it.  But, if your just going to put put around town and take the kids to the park, 450 hp is plenty and keep the 3 or 4 speed.  Otherwise, your literally just wasting money that can be more better spent on other things.

[1974dodgecharger]

LMAO, thinking the same thing talking about expensive, but yet saids he has a hemi with 700hp plus.

overdrive 

Agreed, but ridiculously expensive.   

Dane

Did I read this correctly??? You have a 713 HP HEMI, clearly by the standards of the board here in the 5-speed from Passion Perf., you should be able to afford a newer 5-speed easily....Yet, you say they are rediculously expensive...

[Dino]

So you guys have unlimited funds?  Money does run out you know.  Besides the guy asked a question, not our opinion on how to spend his money.

[Daytona Guy]

I guess I can always do the trany overdrive later - and change the ring gear out (250.00) - But for now I just have to make do. The idea is to cruse, and go fast, and sound crazy good. No gear is going to stay locked in with this car at 700 HP even with my 12' wide back tires.

About the money - that reasoning makes no sense. That is like saying, "If you have enough money to buy a $40,000.00 car, you have enough for a 42,000.00 car". No, 40K is the limit. I have chosen for now to put it in the motor, because if you don't go big, you go home. Once you buy a 426 425HP (or so), you can't take it to 572 later, while I can do a trany change down the road

The issue is 3.23's or 2.94's and does anyone have any used 2.94's ring and pinion I can buy? Can't find them at all.

Dane

[Dino]

2:94's and similar can be found in the plain mopars.  Mine came out of a 65 Coronet.  Be aware that they likely are all 741 cases although I haven't had an issue with mine behind a 440.

I know of one 742 case with open 3:23 for sale in Detroit but he's asking $300 which is close to sure grip money.

Any junkyards with old mopars near you?

[JB400]

If you go big, you stay home.  You can't afford to pull it out of the driveway.







Just pickin on ya

[1974dodgecharger]

Good point, but I still think he knows what to do he is just bored so he is asking questions while he sits and looks at his beauty of a engine he has in his charger 

2:94's and similar can be found in the plain mopars.  Mine came out of a 65 Coronet.  Be aware that they likely are all 741 cases although I haven't had an issue with mine behind a 440.

I know of one 742 case with open 3:23 for sale in Detroit but he's asking $300 which is close to sure grip money.

Any junkyards with old mopars near you?

[Cooter]

So you guys have unlimited funds?  Money does run out you know.  Besides the guy asked a question, not our opinion on how to spend his money.

Certainly not Dino, but While i'll most likely "Never go big or go home", I DID reply in that Passion 5-speed thread about how "Rediculously overpriced" it was and got handed the ol "If you have enough money for a high end car, you have enough for the tranny" response....

Yes, he did ask a question, but also made a statement about how overpriced the OD was. THAT was what I was replying/implying to....


IMO, if you spent a sh*tload on the engine and have nothing left for the trans, then someone made a mistake somewhere. Too much engine? Too much paint job? Too much whatever. I don't think a 700 HP HEMI will have very good street manners in OD in the long run anyway. It takes ALOT of camshaft to make those numbers without forced induction of some sort, Even in a Hemi. Ever tried to drive a Big cammed engine in OD? I have and it SUCKS fuel, Drives like it has NO balls as it's out of it's power band, Lopes uncontrollably, etc.
So to offer my input on the OD? Simple...Don't do it.

[tan top]

yeah thats true  ,  big cam with lots of duration  , tightish converter & 2:94  gears , for the higway , not a good combo ,
 mine  run/ran awesome over  2000 rpm  , but slow speed,   round town , stop start  , holdling in drive with foot on the brake while in traffic or on a lncline , go from neutral to drive ,rpm will drop loads , cause of the tight converter  & lope / chug  , not best choice  ,    if out on the higway all time would not have been a problem .  

[Daytona Guy]

So you guys have unlimited funds?  Money does run out you know.  Besides the guy asked a question, not our opinion on how to spend his money.

Certainly not Dino, but While i'll most likely "Never go big or go home", I DID reply in that Passion 5-speed thread about how "Rediculously overpriced" it was and got handed the ol "If you have enough money for a high end car, you have enough for the tranny" response....

Yes, he did ask a question, but also made a statement about how overpriced the OD was. THAT was what I was replying/implying to....


IMO, if you spent a sh*tload on the engine and have nothing left for the trans, then someone made a mistake somewhere. Too much engine? Too much paint job? Too much whatever. I don't think a 700 HP HEMI will have very good street manners in OD in the long run anyway. It takes ALOT of camshaft to make those numbers without forced induction of some sort, Even in a Hemi. Ever tried to drive a Big cammed engine in OD? I have and it SUCKS fuel, Drives like it has NO balls as it's out of it's power band, Lopes uncontrollably, etc.
So to offer my input on the OD? Simple...Don't do it.

Thank you for your input - this is what I wanted so you are fine with me - it helps to sort it all out. Don't get to far out on 700 HP out of a 572. That really does not take much to get there. When I put on my cast IRON manifold it will pull it down to 650 at least and that is not much over the 1 HP per ci. Plus, this big displacement makes for better drivability so that cam is not that big for these cubes. I do have enough money for the good build on my 727, I'm not putting garbage behind it. Not enough time and money for the overdrive.

[red69superbee]

someone mentioned the 518, whats the good or bad of those.Or is the adapter and trans tunnel work much?Which years are the one to look for?

[Daytona Guy]

someone mentioned the 518, whats the good or bad of those.Or is the adapter and trans tunnel work much?Which years are the one to look for?

To build one for HP runs 3k min and then you need to retro fit it.

Dane

[cdr]

someone mentioned the 518, whats the good or bad of those.Or is the adapter and trans tunnel work much?Which years are the one to look for?

To build one for HP runs 3k min and then you need to retro fit it.

Dane

someone told you a fib ,on the cost to build one,the front is a 727,how much is it to build a 727??,they hold up behind a turbo diesel !! the adaptor from jw bell is $345.00  http://www.dodgecharger.com/forum/index.php/topic,90903.msg1099730.html#msg1099730

[DAY CLONA]

[quote ]

Rearend size - some like'm big - some like'm small - your o-pinion
[/quote]




An overdrive IMHO is a required part of the build nowadays, as much as 4 wheel discs are, and the required suspension mods to accompany them,... horsepower: as much as you can afford.... rear gearing, I always favor 3:90-4:10 ratios, I generally favor Keisler TKO  .64 OD 5 spds behind BBlk 440 or HEMI builds, plenty of stump pulling power, and quickness on the street, 140-150 mph topend speeds on the track/course/highway/etc...and even with 600 HP builds/multi-carbs, still manage 16+ MPG at 70-80 MPH cruising during events like HotRod Power Tours, or cross country driving.....your fooling yourself if you think your going to run 700 HP with a 1:1 transmission final with 2:70-2:80 rear gears, the car is going to be a dog thru out the lower RPM range, esp the HEMI, it loves the upper RPM range...


Mike

[RednblackAttack72]

Hey dad I still trade you if you want to!

[Daytona Guy]

[quote ]

Rearend size - some like'm big - some like'm small - your o-pinion

An overdrive IMHO is a required part of the build nowadays, as much as 4 wheel discs are, and the required suspension mods to accompany them,... horsepower: as much as you can afford.... rear gearing, I always favor 3:90-4:10 ratios, I generally favor Keisler TKO  .64 OD 5 spds behind BBlk 440 or HEMI builds, plenty of stump pulling power, and quickness on the street, 140-150 mph topend speeds on the track/course/highway/etc...and even with 600 HP builds/multi-carbs, still manage 16+ MPG at 70-80 MPH cruising during events like HotRod Power Tours, or cross country driving.....your fooling yourself if you think your going to run 700 HP with a 1:1 transmission final with 2:70-2:80 rear gears, the car is going to be a dog thru out the lower RPM range, esp the HEMI, it loves the upper RPM range...


Mike
[/quote]

Who said anything about 2.70 or 2.80 rear gears? 2.94's and 3.23's yes. Would love to have 3.90 and an overdrive. Just not happening this year. I still do not think people are computing this 700 HP (it's not a 440 - but a stroked 572), On Pump gas, A 4000 lb car, 2500 stall, a moderate cam, a streatable build, with this trq there is no way this will be a dog through the lower RPM range with a 2500 stall. It has 500 HP and 695 trg at 3500rpms for gosh sakes.  A roller cam that smooths out at 1500-2000 RPMs with these trg numbers - not a dog.

Who has that bird in the mag that is running 600 HP with 2.42's?

Dane

[Cooter]

Lemme see if I can put into perspective when running those 4:10 gears and overdrive. Will it work? Sure...Will it increase fuel mileage? Sure...
Does almost everybody here try it and complain about uncontrolable vibrations? Sure....


Do you have any idea what the driveshaft RPM is in OD @ say 80 MPH with 4:10's?

Lemme put it this way, you would have almost certainly grenaded that 572 if spun that high....

All those cars you see on YouTube making 1000 HP and getting 20 MPG are high dollar rides, as are most of them on that PT thingy. Sure I read about 'em in Hot Rod mag and see many of 'em broke down on the Interstate needing Roller Rocker arms replaced, or lifters needed to be replaced 15 years ago on that .950 Lift Solid Roller cam that was plucked from the "Race" side of the Comp. Cams catalog. (Like anybody carries around a Wad of cash to afford a full set of Roller rockers (at least $1000.00 From T&D), at the local Summit Racing Speed shop)...

Sure, there are a couple low dollar rides out there, but for the most part many are like yours here. $30,000 engine and a $3K trans.

[BrianShaughnessy]

Using my friend George's 572 Hemi Road Runner as an example...      well...  first off he races it so it's a Dana 60 and a Cope 727.  With 4.30's it ran low 10's @ 129.    But he also got about 5mpg and didn't enjoy driving it anywhere.

So he put in a gear vendors...   cut down the revs and upped the mpg a bit.   But still not driving to the cruise night friendly.

So last year after the Cope 727 oil pump drive went bang after the last trip to the track he went with 3.73 gears and then he started driving it around more cause I think he was actually getting more than single digits for mpgs.   maybe.


I dunno about 8.75 and 700 hp in a heavy car.   It's a tossup.  Good luck.      So far project Sinnamon is scheduled for 727 / 8.75 with 3.23 behind a 500 stroker so I'm probably pushing my luck also.

[Daytona Guy]

Using my friend George's 572 Hemi Road Runner as an example...      well...  first off he races it so it's a Dana 60 and a Cope 727.  With 4.30's it ran low 10's @ 129.    But he also got about 5mpg and didn't enjoy driving it anywhere.

So he put in a gear vendors...   cut down the revs and upped the mpg a bit.   But still not driving to the cruise night friendly.

So last year after the Cope 727 oil pump drive went bang after the last trip to the track he went with 3.73 gears and then he started driving it around more cause I think he was actually getting more than single digits for mpgs.   maybe.


I dunno about 8.75 and 700 hp in a heavy car.   It's a tossup.  Good luck.      So far project Sinnamon is scheduled for 727 / 8.75 with 3.23 behind a 500 stroker so I'm probably pushing my luck also.

I'm running these size tires 26" on the new build. That too comes into play.

WOW nice car! Who built his engine? - don't plan on doing the quarter with my car. Did the race thing - tore up my car back in the day. I just enjoy getting on the freeways, and punching it when a fart car goes by 

There are variables that make this engine street friendly. Because of the displacement this 572 will run smoother than a 440 with the same duration. Let's look at the numbers... This is a Comp 426 cam that is considered mild for a 426 (.235/249 or a 282 ad), that may run a "little rough  :nana:on idle". But in a 572 that will be tamed way down.  In my 440 I am running almost this very duration with 3.23's and I have plenty of power and trq through the RMP range. The RPM range for this cam in a 426 is 2200-6000 and in a 572 will be 2000-6300 with a hydr roller. Think about it, this is 150 cubes bigger than a 426, that is more of a cube difference of a 360 to a 440. Cams behave differently with more cubes.

If I shoot for a cruising speed of 55-70 @ 2800.00 RMP, it will be doing well without stressing this valve train on 3 hour drives.   Realize too that my tires are only 26". The idea in this build was to get a streetable engine with a lot of HP without having to get my HP from making the engine unfriendly to drive. Displacement was the answer. Again, not planning on racing this car.
Dane  

[Troy]

Look at it this way - you're never going to "hook up" on the street with that much power so don't worry so much about whether the transmission will live behind the Hemi. I'd slap in an A518 and be done with it. The adapter and driveshaft will cost you but then you don't have to compromise on the gear selection (which will make driving the car miserable). I had 2.76s behind my 440 Six Pack with 28" tires and could cruise all day ay 80-85 mph and get respectable mileage - almost 17 mpg - doing it. However, stoplight to stoplight was miserable! It felt like I was melting the clutch every time I tried to get moving. I switched to 3.91s and it was a lot more fun on the street but dropped my highway cruise speed to 61 mph(!!!) before the secondaries were open. This was at 3,100 RPM. Fuel mileage was cut in half if I ran it any faster. I am now running 3.23s and can cruise just above 70 at about 3,000 RPM. I've lost about 2 mpg this way but the car is still very responsive at low speeds. If I had an overdrive gear I could have kept the 3.91s and still had great highway performance. Best of both worlds!

The thing you need to pay careful attention to is engine RPM. I'm guessing that Hemi puts out most of its power at higher RPM. You do NOT want to "lug" the engine very often. You probably also don't want to run around at 3,500-4,000 RPM all the time either. If you're running 2.76 gears with an automatic on back roads you'll only be turning 1,900-2,100 RPM for extended periods of time. You'll want to be on the open road all the time. Your best bet in that case would be with something like a Gear Vendors unit so you can either flip the switch or have it automatically come on once you hit the highway. Yeah, it's $2,500 or so but you're driving experience will be much better!

Troy

[Cooter]

Are you going after an OD for Fuel Mileage? Because if you are, a 700 HP Hemi isn't gonna get and mileage i don't care if you got a tailwind behind you, with a sail on the roof, and a couple electric motors in it. 572 C.I. is ALOT of engine to keep fed. Or, are you after the OD to keep from lunching Lifters/cam/valve springs every five minutes?

With statements like "I'm not gonna race it", but I want a Hemi Putting out 700 HP...Hmmm, I coulda had a LOT more fun with a well built, 500 HP 440 and beat the hell outta the Hemi @ 572 Inches on Fuel mileage. But, that's just me.

[JB400]

Let's put it this way, at least he is doing his part to help out the economy

[Mike DC]

                           
Doesn't somebody make a lower 1st & 2nd gearset for the 727 now?  (like the late 70s 904s had)  I think I remember reading that somewhere.  


This very tame 572" Hemi seems ideally suited to a widely-spaced gearset.  Put a 2.94 or something in the axle and rely on the lowered 1st & 2nd gears to keep the car from being a dog at the stoplights.  
                   

[Ranger Max]

.

[Daytona Guy]

When I see "lug" the engine down, I'm not sure if anyone is reading the numbers on this engine that I gave. I will not be able to lug this engine down with these trq numbers with this cam and trq converter. That is what Indy told me as well. Everyone wants to look at the 700 HP, and lose sight of the fact that it is a 572 ci. That is only 128 cubes to HP increase. That is not that big of a deal for a HEMI. The 426 with a tame cam was 425 HP. With my exhaust manifolds I will be pushing only 650 HP. You have to turn the 440 behavior off in your mind – they will not translate. Think of it more like the 500 ci Cadillac engine when it comes to trq. This engine has @ 2800 RPM 500 ft-trq and 325 HP at the same RPM.  Try lugging that? My happy spot has more to do with the converter stall. My driving range can't fall under my stall – that will overheat my tranny on a cruse.

Troy, yes, down the road I plan in making that move to an OD. What was your stall? The 2.76's is too low for me, I know, but 2.94's with 26" tires, 2" smaller than yours, will put this in the sweet spot, that is, 2800-3000 RPM @ 55-70HPH. Around town it will stay in1st and 2nd gear. From light to light with a 2200-2500 stall – should make that a fun trip

Again, HP without crazy mods - and trq to spare. It's easy HP and they freaking look and sound awesome. My HEMI friends have told me time and time again that their MP 426 HEMI's have no go to them - like they feel they should. I hope I solved that for me.



Thanks Mike

Dane

[Dino]

2:96 with near 26" tires is what I'm running and yeah it's very driveable just about anywhere.

[Brass]

Without an overdrive, the 3.23 is the perfect gear in my mind.  After getting past some initial unease, I wind my car up regularly at freeway speeds from Seattle to Portland and back.  Yes, it seems to prefer cruising at an easy 60 but 70 MPH is still under 3,000 rpm with 26" tires, and I'll top 80 for short stretches too.  Yet around town there's enough torque/stall to do very violent burnouts.  But a gear vendors w/3.55 would be joyous.  Some day...

[Daytona Guy]

Without an overdrive, the 3.23 is the perfect gear in my mind.  After getting past some initial unease, I wind my car up regularly at freeway speeds from Seattle to Portland and back.  Yes, it seems to prefer cruising at an easy 60 but 70 MPH is still under 3,000 rpm with 26" tires, and I'll top 80 for short stretches too.  Yet around town there's enough torque/stall to do very violent burnouts.  But a gear vendors w/3.55 would be joyous.  Some day...

OK, this is interesting. I have 3.23's and my tac reads 3500 @ 65mph. What gives? If I could go 70 with my RPM's just under 3000, I will go with 3.23's because that seemed to be the standard for the 70 Charger R/T auto with the 440 Mag. But in my Yellow car I do not like my 3.23's. I guess my Tac could be off - but it also sounds windy too???

Dane

[bill440rt]

Not sure if they make one strong enough, but if automatic OD's are your thing you might want to look into one by Keisler. Especially if you're in the market for something "bolt-in" without a lot of fabbing or parts scrounging.
I priced it out compared to a GV early in my build. When factoring in rebuilding a 727 along with a GV unit the Keisler option was actually much cheaper. This was partly due because it's not just a trans, it comes with everything else: converter, crossmember, driveshaft, tranny cooler, lines, harnesses, etc etc. Very minor mods needed to install it.
My car "only" has around 520hp, though. I'm running 3:91s with a 27" or so tall tire. Very smooth & responsive, plenty of power for the street. Other than road feel at the steering wheel, there is ZERO vibrations at highway speeds, well, at least up to 90 mph.  

BTW, my other car with 3:55's & a 727 screams at highway speeds, too.

[Rolling_Thunder]

Doing the math on mine...     I will be at 80mph @ 1660 RPM...     

28.5" tall tire with a 6-speed manual trans... 

[cdr]

 

[Daytona Guy]

Doing the math on mine...     I will be at 80mph @ 1660 RPM...    

28.5" tall tire with a 6-speed manual trans...  

You are killing me

Dane

[JB400]

Doing the math on mine...     I will be at 80mph @ 1660 RPM...     

28.5" tall tire with a 6-speed manual trans... 

Sounds like a 5 speed would have been alright for you.  How often do you get it over 120?

[Brass]

Without an overdrive, the 3.23 is the perfect gear in my mind.  After getting past some initial unease, I wind my car up regularly at freeway speeds from Seattle to Portland and back.  Yes, it seems to prefer cruising at an easy 60 but 70 MPH is still under 3,000 rpm with 26" tires, and I'll top 80 for short stretches too.  Yet around town there's enough torque/stall to do very violent burnouts.  But a gear vendors w/3.55 would be joyous.  Some day...

OK, this is interesting. I have 3.23's and my tac reads 3500 @ 65mph. What gives? If I could go 70 with my RPM's just under 3000, I will go with 3.23's because that seemed to be the standard for the 70 Charger R/T auto with the 440 Mag. But in my Yellow car I do not like my 3.23's. I guess my Tac could be off - but it also sounds windy too???

Dane

I suppose my tach could be the one that is off but my experience seems to conform with this.  (At least in the ball park):  http://vexer.com/automotive-tools/speed-rpm-calculator

Yes - the revs seem a little windy.  But then again, these cars can get pretty loud on the freeway which I think also lends to that perception.

[Daytona Guy]

Without an overdrive, the 3.23 is the perfect gear in my mind.  After getting past some initial unease, I wind my car up regularly at freeway speeds from Seattle to Portland and back.  Yes, it seems to prefer cruising at an easy 60 but 70 MPH is still under 3,000 rpm with 26" tires, and I'll top 80 for short stretches too.  Yet around town there's enough torque/stall to do very violent burnouts.  But a gear vendors w/3.55 would be joyous.  Some day...

OK, this is interesting. I have 3.23's and my tac reads 3500 @ 65mph. What gives? If I could go 70 with my RPM's just under 3000, I will go with 3.23's because that seemed to be the standard for the 70 Charger R/T auto with the 440 Mag. But in my Yellow car I do not like my 3.23's. I guess my Tac could be off - but it also sounds windy too???

Dane

I suppose my tach could be the one that is off but my experience seems to conform with this.  (At least in the ball park):  http://vexer.com/automotive-tools/speed-rpm-calculator

Yes - the revs seem a little windy.  But then again, these cars can get pretty loud on the freeway which I think also lends to that perception.

That is freaking cool - great find



I'm sure these converters slip - not sure how much, but if they went to far as to lock them up for gas savings they must slip a lot. the 3.23's are too high for me. My tires might be smaller than I think. I think my tac is off too.

Dane

[Lee A]

Why not go with 2.76s a powerful car like that would make up the differance no problem and still be able to go 70 to 80 revving about 2000 to 2200

[Daytona Guy]

Why not go with 2.76s a powerful car like that would make up the differance no problem and still be able to go 70 to 80 revving about 2000 to 2200

That would put me to far bellow my 2200 stall. I would need a more mild cam - and a lower stall speed on my converter.

Dane

[Daytona Guy]

What a great idea NYMIKE- make the first two gears lower - then the 3rd gear is 1 to 1 with 2.76's as the overdrive. By the time you get to three - in the 1/8 mile track you are past the line.

Dane

[Troy]

Dane, all my cars are 4-speeds at the moment. No stall speed to worry about.

Troy

[Mike DC]

What a great idea NYMIKE- make the first two gears lower - then the 3rd gear is 1 to 1 with 2.76's as the overdrive. By the time you get to three - in the 1/8 mile track you are past the line.

I think the lowered 1st gear for the 727s was a racing piece.  Cost like several hundred bucks.  Not sure if they also had a lower 2nd for it or not.  I think the lower 1st was like a 2.77 or 2.75.  (the regular 727's 1st gear is 2.45) 

I've heard people reference the lower sets for 727s a bunch of times over the years but I don't know where to get one. 


Do the math, and it makes a 2.76 axle pull like a 3.23 during 1st gear.  Or a 2.94 axle would feel like a 3.40-ish axle in 1st gear.

[472 R/T SE]

I gotta agree with Cooter on this.  Did I just type that?

Dane, you're gonna have all this $$ spent on that car & tell everyone you're running a 2:94 peg leg?

Sorry but I don't get it.  Sell that yellow beast if you're needing money to finish the blue one the right way?  You know I can prolly hook you up with a buyer.

Gear Vendors OD is ridiculously expensive?  There's a Hot Rod shop down southwest of Portland that I got mine.  You're not suppose to discount Gear Vendors but he does.  I hooked 3 or 4 members' up here with the same price I got.  I can get you a price & their contact # if you'd like.
You need to go for a ride in a GV ride or better yet drive one.   While my car's not the animal yours will be it's close.  I posted a pic of the dyno board @ a Baxter Auto Parts Dyno Day right after we put the motor in.  I actually took 2nd & they gave me a trophy & gift certificate.  There were some bad ass rides there that day so it was cool that Mopar was 1st & 2nd.

As Cooter has mentioned the GVOD spins the driveshaft entirely too much resulting in vibration.  That, I'll agree with.  My only problem with it has been none of my friends have the gears to keep up with me.  I will say River kept up with me in his 3:23 geared car on a trip to the Charger meet in Kent.  We got there in 2 hours if that tells you anything.

[472 R/T SE]

I might also mention when I parade up to Seattle with my Chrysler R/T buddies I have to leave the OD off otherwise the motor starts lugging up.   HEMIS' LIKE RPM's.

My car winds up through the gears like a small block.  You really need to try & come up here & drive my car.  We can all tell you stuff until we're blue in the face so until you actually drive one you don't know WTF you're talking about.  I say that smiling.   

[cdr]

for me when i started my project one of the first things to do was acquiring my overdrive & if you get the correct ujoint size & drive shaft diameter & have it high speed balanced it want vibrate 

[Daytona Guy]

[Daytona Guy]

I gotta agree with Cooter on this.  Did I just type that?

Dane, you're gonna have all this $$ spent on that car & tell everyone you're running a 2:94 peg leg?

Sorry but I don't get it.  Sell that yellow beast if you're needing money to finish the blue one the right way?  You know I can prolly hook you up with a buyer.

Gear Vendors OD is ridiculously expensive?  There's a Hot Rod shop down southwest of Portland that I got mine.  You're not suppose to discount Gear Vendors but he does.  I hooked 3 or 4 members' up here with the same price I got.  I can get you a price & their contact # if you'd like.
You need to go for a ride in a GV ride or better yet drive one.   While my car's not the animal yours will be it's close.  I posted a pic of the dyno board @ a Baxter Auto Parts Dyno Day right after we put the motor in.  I actually took 2nd & they gave me a trophy & gift certificate.  There were some bad ass rides there that day so it was cool that Mopar was 1st & 2nd.

As Cooter has mentioned the GVOD spins the driveshaft entirely too much resulting in vibration.  That, I'll agree with.  My only problem with it has been none of my friends have the gears to keep up with me.  I will say River kept up with me in his 3:23 geared car on a trip to the Charger meet in Kent.  We got there in 2 hours if that tells you anything.

I will have to respectfully disagree. I have got this far with by rides and builds for 30 years because I think through things and weigh them out using numbers, experience and my gut  – even against conventional wisdom.

Again this is not a 426, or a 472, it is A 572. I hit 543 trq at 2800rpms  - You Hit that At what RPM? I hit 738 TRQ at 4200rpms and that is the trq I will get when I shift down – boom (I know yours was byno'd differently). What is your cam duration? Does anyone read what my numbers are for this build??? Does anyone read how and why I built this? I do appreciate opinions – but still - read the numbers and tell me it will not work using numbers and facts.

What is your tire size, your cam duration, and stall?

One thing is that with 2.94's at freeway speeds kicking down is a blast. In my Yellow Daytona, I can't kick down on the freeway – or it will be at 5500 and go nowhere fast.
Anyone read the MM Mag (2006) Bird with a built 440 dual quad set up, with an overdrive he runs 2.76 gears. He was not too embarrassed to be on the cover!

I couldn't give a rats behind what people think about my ring gear size, really Better yet, I will do you one better (wink), after I get this thing going I will take you for a ride and let you see how it feels. If I'm wrong, I will be the first to admit I screwed up. So I get to spend 250.00 and jump up to a 3.23 and spend a day changing it, Big deal. I will only run 3.55's after I get an overdrive, and only if I am very unhappy with what I have. We will have to wait and see Then we can cruse up to Kent - side my side Love ya Man.

I will be very interested in the GV OD – let's talk.

Dane

[Daytona Guy]

I might also mention when I parade up to Seattle with my Chrysler R/T buddies I have to leave the OD off otherwise the motor starts lugging up.   HEMIS' LIKE RPM's.

My car winds up through the gears like a small block.  You really need to try & come up here & drive my car.  We can all tell you stuff until we're blue in the face so until you actually drive one you don't know WTF you're talking about.  I say that smiling.  

Explain to me how in the world your HEMI is lugging up on the freeway? At what RPM? What are they doing 45 MPH What gears are you running? How is your Motor tuned? That sounds like a tuning issue. Again, give me your specs on your cam. What is your cams operating range? Are those Dyno numbers a Dyno they had at Baxters? - or did one need to bring their Dyno sheet? If those numbers are at the wheels, then your gears and everything comes into play - if they are not crank numbers. BTW - Nice numbers - What was the Polara running?

This engine's Cam range is 2000-6000. I will be at 2800-3300 cruising with 500 trq and 350 ph (just waiting to take a deep breath Show my why this will not work?

Dane

[Troy]

I am obviously no expert but I was thinking more about the carbs not liking that low RPM for an extended time. If you don't think it will be a problem then go ahead. I got to drive Hemigeno's 69 Hemi once and he wasn't happy with me shifting early like I do in my cars (single 4bbl or Six Pack). Your car has a lot more power than his (mostly) stock Hemi so I'd imagine the jetting will be bumped up as well. Gotta keep the RPMs up! Depending on your overall tire height I'd say a 2.94 might be ok. I think a 2.76 is going to be too low - unless you stay with a stock height (26") tire. I'm pretty much running 3.23s in all my cars right now with 28" rear tires which gives me an "effective ratio" right around 3.01 I believe. I know I won't go to 3.55/3.91/4.10 until I have an overdrive because it's too limiting on the highway. I think a 295/50-15 is almost 29" tall and the 3.23 would be nearly perfect. I'm not sure of any equivalent tires for larger rims. Mike Musto (Mr Angry) would know - I believe he runs 19s on front and 20s on back and routinely runs high speeds. His 68 still had a 727 with a GV in it last time I checked.

Troy

[BrianShaughnessy]

295/50/15 is 26" tall...   hard to come by 295/60/15 would be 29".


That was a great link for the rpm / tire sizer deal.    I believe I'm going 275/50/17 which are 27".    Puts me around 2750 rpm at 70mph w/ 3.23's.   

[firefighter3931]

My rpm's can't be too low for my cam .557/.526 -- .235/.249 @ 50 (converter will be 2300-2500).

That's a small cam for 572ci.....no problem using it with a 2000 stall even 

That engine should easily pull 18-20 inches of vacuum and run a PB booster no problem 

The 8.75 is plenty strong as long as the car doesn't dead hook, which it will never do with street tires. 

A 2.94 ratio would be my choice. I'd also suggest you get a quality tq converter from Dynamic/Turbo Action to compliment the power of the stroker. A nice HD driveshaft with forged Yokes and 7290 U-joints as well. 


Ron

[Daytona Guy]

My rpm's can't be too low for my cam .557/.526 -- .235/.249 @ 50 (converter will be 2300-2500).

That's a small cam for 572ci.....no problem using it with a 2000 stall even 

That engine should easily pull 18-20 inches of vacuum and run a PB booster no problem 

The 8.75 is plenty strong as long as the car doesn't dead hook, which it will never do with street tires. 

A 2.94 ratio would be my choice. I'd also suggest you get a quality tq converter from Dynamic/Turbo Action to compliment the power of the stroker. A nice HD driveshaft with forged Yokes and 7290 U-joints as well. 


Ron

You can't seem to get a Quality trq converter under 2200-2500. I got a Hughes - My tranny guy is sold on them.