rearend choices ,stock class?

joe cool · 06-22-2014, 07:13 PM

I have been reading about three 57 chevy's that ran stock class back in the late 60's early 70s. One of the magazine articles mentioned Mopar 4;88 gears. Did they allow rear end swaps back then or did they adapt the Mopar gears to the Chevy drop out? I had been told the 55-57 rears were very fragile ,was the 57 Pontiac or Olds able to be used?
Thanks for the info,just trying to learn me something.
Joe Keightley

Ed Wright · 06-22-2014, 07:29 PM

We had to run the factory rear ends back then. The '57 Pontiac rears pretty much bolted right in. We had gears as low as 6.14 for the originals. They were fragile. Of course, we were limited to 7" tires also.

Aubrey N Bruneau · 06-22-2014, 08:32 PM

With anything resembling a Stocker small block in a 55-57, a rear end swap is quite unnecessary. I designed my own bearing cap girdles. Convert the inside of the original ( or "Nitro Gear reproduction ) Dana Power Lok posi unit to 30 spline side gears, and get aftermarket axles made for it.
then...
run it

Ed Wright · 06-22-2014, 09:33 PM

I had all that in my N/S '56, then began spitting the pinion out the front. I had the dual quad, solid lifter Corvette engine, side stepping the clutch at 7500. The hydraulic lifter guys, leaving lower, didn't seem to have that problem. I drilled & tapped for 1/2" Allen bolts out the front to stop it from simply breaking the wholevcarrier bearing bosses off after stopping the caps from breaking. It spit a few pinions out on the ground about the time they did away with Stock, and made us SS cars. We could change to other "corporate" rears then. I put a '57 Pontiac rear under it then.

Aubrey N Bruneau · 06-23-2014, 12:47 AM

That's nasty, Ed....
I too, have broken many of these in the past. Bent housing, twisted axles, broken caps. NEVER cracked or broke a center casting ( pumpkin )... and I've been running 3600-3700 pound 409 stick cars for a LONG time.

Greg Reimer 7376 · 06-24-2014, 09:09 AM

A friend of mine, about 40 years ago, had a '64 Impala SS hardtop, 340 horse 409, factory 4 speed. He knew the meaning of the term "driveline failure", he could have written the book. One day, he was getting on the eastbound San Bernardino Freeway, ran through the gears, and power shifted fourth for all he was worth. The noise of what happened about scared him through the window. The center carrier casting broke off and the pinion gear, the drive line and everything left out the back of the car and bounced around the freeway for a while. He got stopped, at the end of the trail of 90 wt,and a glance under the car revealed a giant jagged hole where the pinion bearing support and gear was. You just can't abuse a 4000 pound car with a 4 speed with that rear end and not expect disaster.

06-22-2014, 07:13 PM	#1
joe cool Junior Member Join Date: Jul 2012 Location: southwest iowa Posts: 53 Likes: 3 Liked 5 Times in 3 Posts	rearend choices ,stock class? I have been reading about three 57 chevy's that ran stock class back in the late 60's early 70s. One of the magazine articles mentioned Mopar 4;88 gears. Did they allow rear end swaps back then or did they adapt the Mopar gears to the Chevy drop out? I had been told the 55-57 rears were very fragile ,was the 57 Pontiac or Olds able to be used? Thanks for the info,just trying to learn me something. Joe Keightley __________________ Joe Keightley Pacific Junction Iowa

06-22-2014, 07:29 PM	#2
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: rearend choices ,stock class? We had to run the factory rear ends back then. The '57 Pontiac rears pretty much bolted right in. We had gears as low as 6.14 for the originals. They were fragile. Of course, we were limited to 7" tires also. __________________ Ed Wright 4156 SS/JA

06-22-2014, 08:32 PM	#3
Aubrey N Bruneau Member Join Date: Sep 2003 Location: South Eastern Alberta, Canada Posts: 311 Likes: 6 Liked 7 Times in 3 Posts	Re: rearend choices ,stock class? With anything resembling a Stocker small block in a 55-57, a rear end swap is quite unnecessary. I designed my own bearing cap girdles. Convert the inside of the original ( or "Nitro Gear reproduction ) Dana Power Lok posi unit to 30 spline side gears, and get aftermarket axles made for it. then... run it __________________ Aubrey N Bruneau 6409 C/S 62 BelAir sport coupe, 409 HP 409

06-22-2014, 09:33 PM	#4
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: rearend choices ,stock class? I had all that in my N/S '56, then began spitting the pinion out the front. I had the dual quad, solid lifter Corvette engine, side stepping the clutch at 7500. The hydraulic lifter guys, leaving lower, didn't seem to have that problem. I drilled & tapped for 1/2" Allen bolts out the front to stop it from simply breaking the wholevcarrier bearing bosses off after stopping the caps from breaking. It spit a few pinions out on the ground about the time they did away with Stock, and made us SS cars. We could change to other "corporate" rears then. I put a '57 Pontiac rear under it then. __________________ Ed Wright 4156 SS/JA

06-23-2014, 12:47 AM	#5
Aubrey N Bruneau Member Join Date: Sep 2003 Location: South Eastern Alberta, Canada Posts: 311 Likes: 6 Liked 7 Times in 3 Posts	Re: rearend choices ,stock class? That's nasty, Ed.... I too, have broken many of these in the past. Bent housing, twisted axles, broken caps. NEVER cracked or broke a center casting ( pumpkin )... and I've been running 3600-3700 pound 409 stick cars for a LONG time. __________________ Aubrey N Bruneau 6409 C/S 62 BelAir sport coupe, 409 HP 409

06-24-2014, 09:09 AM	#6
Greg Reimer 7376 VIP Member Join Date: Nov 2008 Location: Glendora,Calif. Posts: 1,132 Likes: 172 Liked 698 Times in 216 Posts	Re: rearend choices ,stock class? A friend of mine, about 40 years ago, had a '64 Impala SS hardtop, 340 horse 409, factory 4 speed. He knew the meaning of the term "driveline failure", he could have written the book. One day, he was getting on the eastbound San Bernardino Freeway, ran through the gears, and power shifted fourth for all he was worth. The noise of what happened about scared him through the window. The center carrier casting broke off and the pinion gear, the drive line and everything left out the back of the car and bounced around the freeway for a while. He got stopped, at the end of the trail of 90 wt,and a glance under the car revealed a giant jagged hole where the pinion bearing support and gear was. You just can't abuse a 4000 pound car with a 4 speed with that rear end and not expect disaster.