56 Chevy rear axle?

rod · 07-11-2020, 04:37 PM

any one have experience in putting MoPar side /axle gears in a Chevy [56-64] Dana posi. they were the same posi units, just different parts inside.
I have a line on those parts. just want to be sure they will really interchange before I move forward.
thanks
Rod in AZ

dondon · 07-12-2020, 01:40 AM

I heard it was a common practice years ago so they could run 30 splice mopar axles. I know that chevy posi clutches are different than mopars in that one plate (chev) is about .020 or so thicker than the mopar, and the case halfs will not seat against the other. mopar clutches will work on a chev. I did put a set of chev spiders in a mopar.

Dwight Southerland · 07-13-2020, 08:05 AM

Yes. There was an article in either Car Craft or SS & DI in 1967 that detailed the necessary mods. There were specific MoPar axles that could be modified to fit. Today you could buy axles easily. There was a shim kit you could buy from Chevrolet parts that was used to adjust the clutch pack thickness. I did this in the summer of 1968 to a '57 Chevrolet.

Alan Nyhus · 07-13-2020, 08:38 AM

If you're going to use a posi setup, I'd call Tom's Differentials and talk with them.

I remember that some of the differentials has 8 plates and some had 10. The spider gears were also a weak spot but I believe Tom's makes replacement high strength spider gears. They've been doing these '55-'64 style drop outs for a long time...many of the 409 guys use their stuff. Might be worth the call if you're committed to using a posi. -Al

https://tomsdifferentials.com/toma.html

Dwight Southerland · 07-13-2020, 12:17 PM

Quote:

Originally Posted by Alan Nyhus

If you're going to use a posi setup, I'd call Tom's Differentials and talk with them.

I remember that some of the differentials has 8 plates and some had 10. The spider gears were also a weak spot but I believe Tom's makes replacement high strength spider gears. They've been doing these '55-'64 style drop outs for a long time...many of the 409 guys use their stuff. Might be worth the call if you're committed to using a posi. -Al

https://tomsdifferentials.com/toma.html

X2!

Jeff Stout · 07-13-2020, 01:43 PM

My first car was a 55 Chevy in 1976. 327 4speed. I broke so many spider gears. As soon as the car wheel hopped bam. If I had only knew at the age of 16 this trick.

Mark Yacavone · 07-13-2020, 05:20 PM

We had Chrysler side gears and Henry's Axles in 1970...because we had to.

What are we building here?

Aubrey N Bruneau · 07-17-2020, 11:32 AM

I designed a complete kit for running these rears, which I use in my 62. The Dana "powr-lok" design posi unit is available brand new, already prepared with the 30 spline side gears in it.
Also, bearing cap re-enforcement is mandatory.

jmantle · 07-18-2020, 09:39 PM

[QUOTE=Mark Yacavone;618405]We had Chrysler side gears and Henry's Axles in 1970...because we had to.

Likewise, Chrysler side gears, Henry's axles, shim the clutch pack tight, torque up those weird left hand bolts, then weld the two halves together. Add steel caps and longer cap bolts and it might be good for a few runs with a stick car. Not sure when we first tried this, 67 or 68.

Jim Mantle V/SA 6632

Bob Mulry · 07-22-2020, 03:55 PM

I still have a couple of hams on the shelf that have Stahl & Associates heat treated MOPAR posi side gears to go with my Henry’s Axles in my 1962 Corvette

You also need a steel bearing cap and stack the posi plates 1 internal tang and 1 external tang to make it a locker....

I also welded a doubler plate and 1/2-20 nut to the rear of the housing, so I could tighten it up against the cap for strength....

Don’t forget there are 2 types of posi cases, 1 with 90 degree ramps and the other 120 degree ramps...

I ran either 3.70’s or 5.38’s on the street back in Brooklyn........

07-11-2020, 04:37 PM	#1
rod Member Join Date: Dec 2009 Location: Kingman, NW AZ. in the middle of the longest stretch of Route 66 Posts: 306 Likes: 0 Liked 17 Times in 13 Posts	56 Chevy rear axle? any one have experience in putting MoPar side /axle gears in a Chevy [56-64] Dana posi. they were the same posi units, just different parts inside. I have a line on those parts. just want to be sure they will really interchange before I move forward. thanks Rod in AZ

07-12-2020, 01:40 AM	#2
dondon Junior Member Join Date: Dec 2012 Posts: 26 Likes: 8 Liked 10 Times in 5 Posts	Re: 56 Chevy rear axle? I heard it was a common practice years ago so they could run 30 splice mopar axles. I know that chevy posi clutches are different than mopars in that one plate (chev) is about .020 or so thicker than the mopar, and the case halfs will not seat against the other. mopar clutches will work on a chev. I did put a set of chev spiders in a mopar.

07-13-2020, 08:05 AM	#3
Dwight Southerland VIP Member Join Date: Dec 2001 Location: Arkansas - In the middle of everything. Posts: 1,980 Likes: 52 Liked 724 Times in 177 Posts	Re: 56 Chevy rear axle? Yes. There was an article in either Car Craft or SS & DI in 1967 that detailed the necessary mods. There were specific MoPar axles that could be modified to fit. Today you could buy axles easily. There was a shim kit you could buy from Chevrolet parts that was used to adjust the clutch pack thickness. I did this in the summer of 1968 to a '57 Chevrolet. __________________

07-13-2020, 08:38 AM	#4
Alan Nyhus VIP Member Join Date: Dec 2002 Location: Lower Dakota territory Posts: 1,164 Likes: 1,013 Liked 761 Times in 225 Posts	Re: 56 Chevy rear axle? If you're going to use a posi setup, I'd call Tom's Differentials and talk with them. I remember that some of the differentials has 8 plates and some had 10. The spider gears were also a weak spot but I believe Tom's makes replacement high strength spider gears. They've been doing these '55-'64 style drop outs for a long time...many of the 409 guys use their stuff. Might be worth the call if you're committed to using a posi. -Al https://tomsdifferentials.com/toma.html __________________ "That'll never work....."

07-13-2020, 01:43 PM	#6
Jeff Stout VIP Member Join Date: Dec 2001 Location: phoenix Posts: 1,409 Likes: 53 Liked 655 Times in 255 Posts	Re: 56 Chevy rear axle? My first car was a 55 Chevy in 1976. 327 4speed. I broke so many spider gears. As soon as the car wheel hopped bam. If I had only knew at the age of 16 this trick.

07-13-2020, 05:20 PM	#7
Mark Yacavone Veteran Member Join Date: Mar 2002 Location: Miles From Nowhere Posts: 7,414 Likes: 2,581 Liked 4,447 Times in 1,693 Posts	Re: 56 Chevy rear axle? We had Chrysler side gears and Henry's Axles in 1970...because we had to. What are we building here? __________________ We are lucky we don't get as much Government as we pay for..... Will Rogers

07-17-2020, 11:32 AM	#8
Aubrey N Bruneau Member Join Date: Sep 2003 Location: South Eastern Alberta, Canada Posts: 311 Likes: 6 Liked 7 Times in 3 Posts	Re: 56 Chevy rear axle? I designed a complete kit for running these rears, which I use in my 62. The Dana "powr-lok" design posi unit is available brand new, already prepared with the 30 spline side gears in it. Also, bearing cap re-enforcement is mandatory. __________________ Aubrey N Bruneau 6409 C/S 62 BelAir sport coupe, 409 HP 409

07-18-2020, 09:39 PM	#9
jmantle Member Join Date: Feb 2008 Location: Black Creek, BC Canada Posts: 312 Likes: 62 Liked 137 Times in 67 Posts	Re: 56 Chevy rear axle? [QUOTE=Mark Yacavone;618405]We had Chrysler side gears and Henry's Axles in 1970...because we had to. Likewise, Chrysler side gears, Henry's axles, shim the clutch pack tight, torque up those weird left hand bolts, then weld the two halves together. Add steel caps and longer cap bolts and it might be good for a few runs with a stick car. Not sure when we first tried this, 67 or 68. Jim Mantle V/SA 6632

07-22-2020, 03:55 PM	#10
Bob Mulry VIP Member Join Date: Apr 2002 Location: Coarsegold, CA Posts: 1,017 Likes: 57 Liked 321 Times in 101 Posts	Re: 56 Chevy rear axle? I still have a couple of hams on the shelf that have Stahl & Associates heat treated MOPAR posi side gears to go with my Henry’s Axles in my 1962 Corvette You also need a steel bearing cap and stack the posi plates 1 internal tang and 1 external tang to make it a locker.... I also welded a doubler plate and 1/2-20 nut to the rear of the housing, so I could tighten it up against the cap for strength.... Don’t forget there are 2 types of posi cases, 1 with 90 degree ramps and the other 120 degree ramps... I ran either 3.70’s or 5.38’s on the street back in Brooklyn........ __________________ Bob Mulry 7516 STK A & M Motorsports Last edited by Bob Mulry; 07-22-2020 at 03:58 PM.