I got a 57 Poncho rear end and I'm trying to slip a posi 3rd member from a 59 Pontiac rear in the 57 housing. Now, the rub comes with the fact 57 Pontiacs never came with posi's and they only came with 28 spline axles. In 58, pontiac offered a posi but they went to 31 spline axles.. I could score a pair of 58 [only] pontiac posi [only] axles shafts but it seems like it'd be easier to use a generic 59-64 Olds axle shaft from any old Olds. They're the correct spline but 5/8ths of an inch too long but I have no problem with chop-sawing off a 5/8ths slice from the end of the shafts. What I need to know is if the wheel bearing O.D. from a 57 Pontiac is the same as one for a 59-64 Olds big car. I would also love to know if there is enough spline machined into the olds axles to go all the way in my pontiac rear after cutting off 5/8ths of an inch. I know, these are "shot in the dark" questions but anybody else ever done this?
Saw an add on Ebay yesterday for some Olds axle ends 59-64. It said the bearing size was 3.025. I'm not %100 percent sure but I know it was over 3". Hope that helps.
call the parts store and ask for a bearing for each of those axles,if the part # is the same you're in luck.
Yeah, I can do that tomorrow but I couldn't help but wonder if someone here had possibly done a gasser rear axle using a 57 Poncho unit. As many of these that have been bolted under 55-57 chevys. someone has surely been wanting to make their 57 Poncho rear end a posi.
Rocky-- here is some correct info to help you: '57-8 Olds/Pont had 29 spline, not 28. '59 was when they went to 31 spline. '58 was the first year of posi, and they were 28 spline. But very difficult to obtain and not as strong. You are better off locating a 31-spline posi and then using 31-spline axles. Side note: There were two types of posis (Dana Spicer Powerlok's and Eaton's) and there were three different ratio ranges (2.56 only which is rare in posi, 2.69-3.23 which can hold steeper gears with a 1/4" ring gear spacer though not recommended for drag racing, and 3.42-steeper). Hope that helps. I've been into these rears heavy for 12 years.
Blown...I hit the worng key on the 29-vs 28 axle spline axle shafts..oops! I have the '59, 31 spline posi and wanna use it in my 57 housing. The problemo is the 57 uses 29&7/8ths length, 28 spline axles....oops! 29 spline axles. There is no such thing as a 29&7/8ths, 31 spline axle shaft BUT! full size oldsmobiles used 31 spline axles in their cars too. Their axle shafts are 30.5 inches long, making then a little too long for the 57 Poncho housing. My question is: Will the olds axles work in the pontiac housing with the 31 spline posi if I chop off the ends of the axle shafts? To further confuse the issue, 31 spline Pontiac axle shafts are even longer than the Olds'shafts, with their new "wide track ride" and all, making them quite a bit too long for the poncho housing...
........and I researched the carrier height issues before buying. I have a series 1 carrier. Had a rusty old 2.69 gearset on it and my 3.23's will go on it, keeping with the series one decor.... If nobody here's done this axle shaft swap, I guess I could measure easily enough. Just thought someone here'd possibly already done it. The hollander tells me everything I needed to know about this swap except how far up the axle shafts the splines run, dictating how much axle shaft end I can cut off. Worse case scenerio? Go to my buddy for his 61 pontiac rear end and simply change out my posi 3rd member into the 61 housing...no sweat!
Sorry I can't help with how much exactly to lop off. But, it's obvious you can shorten them. The question is whether or not you need to cut the splines further in and whether or not a shop will do that. On another side note, I HAVE once heard that the two different styles of posi's may require different amounts of spline engagement-- one person told me that he switched posi's or something and then his axles wouldn't go all the way in anymore or something and he needed to shorten them. I don't know the details to give an accurate recount of that though.
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