Technical 1956 Chevy, broken axle. What to do?

I've been thinking about this too with regard to the potential of using a Pontiac rear. When you have vintage wheels, as I do, that becomes another hurdle... although a minor one compared to the rear end cost.

 

I also have a 8.5 10 bolt. Although it would have to be narrowed about 2" I believe.

 

You asked about the GM 10 bolts, and said you want to keep it GM; so, get a Nova/Camaro, 73-81 (NOT earlier or later!) 10 bolt. Has the same size pinion gear "shaft" as a 12 bolt, cheaper than a 12 bolt, and plenty strong. I had a 57 Olds all set up to go into my Sedan Delivery; two third members with Eaton Positractions, one had 4.88 gears, the other had 5.38's. An old pair of Summers Brothers axles, and the spring pads moved (57 Pontiac's are a bolt in for the pad position), plus all new bearings, seals, and brakes. But, someone offered me stupid money for all of it, and I bit. Then I completely went through the stock rear end. In went with a 4.88 Positraction (have a couple extra of those and another with 5.13 gears), I got real lucky and found a pair of aftermarket bearing caps (late 60's/early 70's parts), and bought new Yukon axles (if you go that route, you have to also buy their "special" wheel studs, as stock won't work). I also think one of the biggest things to have is some sort of traction bar to prevent wheel hop; wheel hop really adds to breaking parts. If you have an automatic transmission, then a well built stock rear end should be fine, if it's a manual transmission, then time to step up to the 73-81, ten bolt. My Sedan Delivery has a 4 speed, but I don't drive like I used too, and it has't been out of the garage in almost 4 years.. If you find the correct 12 bolt, they are $$$$$ now. The MOPAR 8-3/4 rears are fairly strong, and the 8.8 and 9 inch Fords are stronger, but they all have a different wheel bolt pattern than you have currently, and that adds to the cost to straighten out. I am Butch/56sedandelivery.
Depending on how close your broken splines/stub are in the third member, you may not need to remove the stub to remove the third member. If you can't remove it because the stub is too long, and you can't get hold of the stub, you're not stuck. Get an 1/8 to 1/4 inch diameter rod that's long enough to reach the stub and also has enough length to work with on your end. Cover it with some rubber fuel hose. Connect your end to an arc welder "turned up", jab it into the stub, turn on the arc welder for just a second or two, and turn it off.. Hopefully, you can pull the stub out. I've seen a friend do that, although it does't always work due to the oil coated environment

 

Well, as I've been told, you should check the tq on the adapters regularly, is that a myth? BP referred to Bolt Pattern.

 

The 10 bolt I have available is out of a '73 Firebird. But, it is a couple inches wider than my '56. If I go that route, I suspect I may be better off just trading it for a Nova rear and go from there.

It's a 4 speed car and I have Cal Tracs on it now. Hopefully I can contact the company and just buy the portion of the bar that bolts at the spring perch since the original '56 housing is smaller diameter.

 

I’ll never race it but I installed an 8.8 in my 56 Ford. Wanting drums, F-150’s had them too and now I have 11x2-1/4” instead of 11x1-3/4” drums in the rear. They have a 2.74 if you don’t have an OD trans and a bunch for them. Discs and posi’s are piled up in the bone yards.

 

Finding any of the good old style rear axles has become a budget breaker these days, brand doesn't seem to matter. If you can't get over putting a different brand of rear end in your car, expect to drop some big coin.

If you really have 500 HP, a 4 speed, and Cal-tracks, most anything stock, even from the glory days, probably won't hold up long either. Its time to put in a rear axle to match up with the rest of your car. Gene

 

My car project came with a "roller" axle I believe to be a'55 to '57 Chevy. You can have it free if you want to get it back together and take it easy until a better set up is ready to go.

Gary

 

Yep. This has been a learning experience as it's about 130-140 more horsepower than anything else I've ever owned.

 

That'd be great! Where are you at in Iowa? You can just p.m. me if you want. Thanks

 

Go see Quick Performance in Ames.

 

Just so you know, the 55-56 axle housings and third members are basically the same, using the same size bearings, although the third member cases are thinner. The 57 housing has the added benefit of a drain plug, and the axle bearings are larger than the 55-56; therefore, the axles won't swap between all three years, so be careful of what you have. Can't use the 57 axles in a 55-56 housing and vice versa. The 55-56 bearings, at least the good original ones, are getting scarce, and the off shore ones don't last long. Course the 55-56 original bearings cost a lot more. Third members do swap 55-64 in full size cars, 55-62 Corvettes (53-55 Corvettes used the same basic gears/bearings as the 49-54 cars, but were open drive-line), and 62-64 Nova (but stay away from the early Nova third members as they use smaller bearings and really light weight third member cases. The axles are smaller also, especially the 4 bolt ones.
I am Butch/56sedandelivery.

 

Bolt in wise without a lot of hassles 68/79 Nova or clone at 60.25 is just .25 wider WMS to WMS than a tri 5 rear. Finding one with a good gear ratio for what you want to do may be a challenge and finding one with posi would be a bigger challenge.
To me early Pontiac or Olds are out unless you just flat have unlimited spending money. Beefy but it would be pretty easy to stick 2 k on one just getting it set up right.

S-10 4X4 is real popular and not spendy in comparison but at 59 inches you loose a half inch on each side and would have to know if you have room to the inside for your wheels to go in a half inch. The majority have 3.7 gears and posi isn't that hard to find. The fancy ZR2's rear is 63 inches wide and that is too wide for a 56.
The few 12 bolts that fit are now in the "collector" category and those who know what they have are going to hammer you on price.
Explorer 8.8 is 59-1/2 wms to wms. I found out the one in my 92 Ranger is 56-1/2. That is one beefy rear axle though.

It seems like my first experience at fishing the broken stub of an axle out of a rear end was figuring out how to snake one out of my buddy's 57 2 door post while I was still in High school. That was the same car that broke the rotor just about every time he did a hard launch and burn out until someone showed him the screw sticking out from the firewall that the cap hit when the engine lifted up due to weak mounts. Before that he bought those 57 Rotors by the handful.

 

Of all the options you have been given, the 9" Ford is going to be the cheapest "look-a -like" for the car than any other, just sayin'.

 

A stock 9 inch is not as strong as most people think. With 500 hp and good traction you can launch the pinion up through the top of the chunk. The weak pinion support on a stock 9 inch is the reason for the Daytona pinion support and then the rear bearing lets go and you have the same issue. Also if you get a rear end out of a Junk yard that has been setting on the ground replace the spring saddles or you could end up doing what I did last weekend at a SEGA race. The saddles collapsed and allowed the whole rear end to rotate upward in the car breaking a 1350 u joint . That was a 5 grand launch on the spec 7 inch Hoosier slick.
Find the right width housing . Buy an aftermarket carrier like the S series from Strange Daytona style pinion support. Good yoke with 1350 u joints. Most aftermarket axles give you the bolt pattern option.
I would go no less than 31 spline on the axles.
I have put down over 650 hp with a 12 bolt with aftermarket axles and a spool and a 1350 u joint. With 10 inch slicks a big block with a transbrake at 3700 lbs. for 2 seasons of racing it almost every weekend sometimes more than one race per weekend.

 

Have they gotten better over the years? My introduction to Quick Performance was probably 20(?) years ago. A local guy had a big block '55 that Quick built a 9" for. I don't know how many times he had to pull that rear for them to fix their f ups.

 

A lot of good info here. I have been so mental about NOT using other make parts that I figure I can't/shouldn't go back now. LOL. I actually had a correct width 3.73 posi 8.8 a few years ago but I sold it for dirt because I couldn't bring myself to put a Ford rearend in the car. And you are right to mention the 1/2" loss on either end of the S10 rear... if I used that my tires would only have almost no clearance on the inside.

Thanks to you guys advice(and a little bit of kick in the a$$) I think I may have found a Pontiac/Olds 9.3 posi. If that doesn't work out, I may just bite the bullet and get a 12 bolt from Moser if I can sell some of my other rear end pieces to help fund it.

 

With regard to the Pontiac/Olds 9.3 rear: Is it '57 to '62 or '57 to '64? I always thought '64 was the last year, but I've heard both.

Also, does it have to be a certain carrier for different gears? I've found a posi but I'm guessing it is the numerically lower(high) gears and I want to be sure it'll work for 3.73s or similar.

 

Looking at your dyno sheet ....oil pressure really drops above 6k ,.....windage ?

 

All the info you could use. https://fabcraftmetalworks.com/

 

You may never need a rearend as beefy as these guys offer but they have been the go-to for 57-64 Olds/Pontiac parts and service.
Edit
Saltflats types faster than I do.

https://fabcraftmetalworks.com/



Pretty lengthy discussion on this HAMB thread.
Here:
https://www.jalopyjournal.com/forum/threads/pontiac-olds-rearend-tech-post-it-here.129676/

 

I know you have warmed to the idea of using another make but here is some info that may be of interest.
https://www.jalopyjournal.com/forum/threads/dearborn-transmission.583129/#:~:text=the dearborn transmission was a heavy duty 3,55 Poncho way back in '67 or so.

In short GM did not have a manual 3 speed that would stand up to the torque of the '60s big blocks. So GM factory installed Ford 3.03 transmissions in their big block sedans...Biscayne, Impala, Olds and Pontiacs....

Performance, period performance, trumps brand loyalty. Even the manufacturers did this on occasion.

 

http://www.bruneauperformance.ca/
these guys have parts to upgrade the stock chevy rear.

EDIT: it seems they only have bearing saddles now, but those with after market axles would help?

 

I have not done this personally so take it with a grain of salt. I was told by an old timer when I was a sprout that you can put an Olds or Poncho chuck in the Chebby housing and use the heavier Olds or Poncho axles. I got an idea he knew what he was talking about. Be worth a try.

 

Chevy


Olds/Pontiac

 

It won't fit. Not even close.

 

Bottom line for the OP is looking at two options, in my opinion.
One is to make the car mobile under its own power for now and plan over the winter on what to do. This option could be a call to Currie, Strange, etc for an axle. Or scour the net for one that will work
Second is future concerns and what he can do to make it last and take abuse.
Maybe he wants a bolt in deal. Maybe he doesn’t want to scour the wrecking yards and do what it takes to make things fit.
We always hear about “time is money”. Well if so, why pull a rear from a yard. Time. The go through the rear. Time/money. Then take axles to be redrilled. Time/money.
Maybe take the easier route and call for a rearend he can spend an afternoon and just bolt in?

 

Of course he will have to specify all GM parts

 

I had read that a while back. Ford made some great parts, I just can't bring myself to use them on this particular car. I've had the car since I was 11 or 12(30 years) and have pretty much always had the same basic idea of what I wanted it to be.

 

I was really torn on the Pontiac vs order a 12 bolt. But, I think I am going to try to go with the Pontiac/Olds rear as I have found a '57 housing pretty reasonable and another one with a posi not far from my folk's place.

As far as getting it back on it's wheels, a member has offered me a stock rear if I come pick it up(about 2 hours each way). HAMBers are great!