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

[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.