Which 10 bolt fits the tri-fives best???

I remember reading somewhere, someday about which 8 1/2" GM 10 bolt rear housing was the right width for my '55 but I am sketchy about the details. I think it was the 68-69 Camaro & 68-74/75-79 Nova axle that was just right, and I just need to replace the spring perches. I have a '79 Trans Am 3.23 posi, but it is over 62" and that seems wide. Any one know what stock 55-57 Chev. is because my car is missing the correct rear. Somebody slapped a coil sprung 7.5" 79 malibu rear in there with the brackets torched off when they pulled out the Ford rear. Thanks for any help.
http://www.youtube.com/watch?v=WKAGUkYBqNY
<input id="gwProxy" type="hidden"><!--Session data--><input onclick="jsCall();" id="jsProxy" type="hidden">

 

I don't have the width of axles, but from backing plate flange to flnge is 55 1/4"

 

55-57 rear is about 60 iniches width at the wheel mounting surface. A 67-69 Camaro/68-72 Nova rear is about the same 60 inches.

Your 79 T/A rearend would need to be careful of wheel offsets.

 

The 8.5 inch ring gear 10 bolt that came along in 1972 is your best bet if you want to go with a 10 bolt. The Nova-Appolo-Omega sized cars have a 60" wide rear end. The Camaros and Firebirds used the same basic rear end but it was about 2"s wider. The rear end cover has the same bolt pattern as the earlier 8.2" 10 bolts so be sure to check the pinion nut size. The 8.5 rear end has an 1.25 inch pinion nut.

 

Yeah, I like the 8.5" rear. GM has updated this basic design recently and calls it the 8.6. The Carrier bearings are larger, and maybe the pinion bearing O.D.? And spline count on the spiders was increased in 89 or 90 I think. But the 8.6 ring and pinion is a drop in. Which is great 'cause many late GM trucks run 3.73 & 4.10 gear. I am gonna grab an X-body(Nova,& sister cars) drum housing from my fav. yard, use my F-body posi unit, and watch Ebay for some cheap used GM 8.6 gears. Thanks guys.

 

I have an early 70's Nova 8.5 10 bolt under mine. I use 8 inch wide wheels with 4.5 inch back spacing and they fit near perfect. It has 4.88 gears and a posi and I haven't been able to break it yet, though I really don't get much traction either.

The guy that had the rear axle before me though had it in the original 72 or so Nova with a set of 12 inch slicks and was racing it. He didn't seem to be able to break it either, though I don't know what kind of power he was making.

Seems to be a pretty good low buck way to go in these cars.

And yes, you will have to move the spring perches a little to make it a simple bolt in.

Good luck!

 

i put a 84 regal rear fit good, just cut off the bracket and get spring perch from the speed shop. weld it on tube.. everything take time, measure, angle