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

[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?