Hey everyone, trying to figure out the best route to go with a rear swap. Our 1972 skylark had the stock open 2.73 geared bop rear. I picked up a 68 Chevelle 10 bolt with posi 3.73, aftermarket axles, and disc brakes. Swapping out the stock one for this but I realize the yokes are different going to the 25 spline Chevelle rear. Is there a 25 spline yoke that measures the same length as the skylarks? Am I going to be lengthening the driveshaft in order to bolt everything back together?
They sell a hermaphrodite adapter U joint that will solve your problem. I just bought one for my 66 with a Chevy 8.2. I'll see if i can find the part number. Google will find it. Edit found it- https://www.rockauto.com/en/parts/dana,530221X,universal+joint,2392 The specs are listed on the site. This should fit your old driveshaft and allow you to use the original 8.2 yoke. Dana spicer 530221x
Oh that would be great! So that u-joint will account for the additional bit of length I need also? Or does the yoke at the trans just slide out a bit further?
Before you order that... Most people here do the swap the other way. The 8.5 that came with your car was a better, stronger rear than the Chevy 8.2. It's not the yoke that's longer on the 8.5, it's the housing. You will probably need to get your driveshaft lengthened and then you should be able to use the adapter ujoint. Hopefully, someone will be along to correct me if I'm wrong.
Yes, the 8.5 has a longer snout. When going the other way from Buick 8.2 to 8.5, you normally have to shorten your driveshaft. The Chevy 8.2 is a weaker C clip rear. I would have built the 8.5 if it was me. I'm guessing you got a great deal on the 8.2.
The 10 bolt 8.5 rear has a longer pinion shaft...and the yoke will be physically longer too. so your talking about making up a 1" to 1 1/4" in length. The u joint will be a 372 Moog / precision 372 / neapco 3-3130 / spicer 5-3022X so yes to properly fit this 8.2 rear in place of the 8.5 original you will likely need a longer drive shaft. and the u joint numbers i gave you which are all the same u-joint 1 1/8" M3R x 1 1/16" 1310 Jim JD race
Yep, I'm going from the 8.5 to the 8.2 simply because I got it for a steal with the gears, posi, and brakes already done. I'll go ahead and get it mounted and then measure the needed driveshaft length. Thanks for all the replies everyone.
Save the old drive shaft for the 8.5 replacement after - Or sell it with nthe 8.5 rear to someone else with a a body GM. Package deal.
