71 8.5 rebuild

So my 1970 sport-wagon has a 71 Buick rear end with bolt in axles as we determined in an earlier thread,

Turns out it has 2.93 gears and a non functional Posi-unit that im pretty sure was working before i swapped out the SP code 350 for a fully built 455 (462ci) motor.
My question is can anyone of the "rear experts" provide me with the correct part numbers to re-due the unit soup to nuts with new seals and everything else i need that i may have overlooked ? and no im not doing the work myself...

From my research just on this site im looking to do--
Eaton Tru trac
30 spline Moser axles
3.73-3.90 Gears ? Brand? cars really not gonna see long highway rides maybe 3.42's would be sufficient?
It has a th400, 28" tires it will see the track here and there but not looking to run a number just a quick street wagon..Thanks!

 

Are you absolutely sure what rear you have? I only ask because the parts will be different. The was a 2:73 available for the 8.5” and a 2:93 available for the 68-70 8.2”. You also need to make sure it didn’t come from something like a Vista Cruiser because the axles are bigger at the bearing and have a larger bearing.

 

I can provide any other pic's if needed, gears feel very low

 

Looks like an 8.5. Now the true sport wagon rear used a set 10 wheel bearing not a set 9......meaning you can buy 33 spline thst will bolt in instead of just 30.

But the only way to know is measure the bearing od

 

Initially i wasnt sure what was in there because it looked like its been in there since day one crud and all so last year i posted a thread for id because the car from factory is supposed to have an 8.2 and a th350 (which it also doesnt) , and all the Guru's identified it as a 71-72 8.5

 

Yes,that is an 8.5” 10-bolt. A pair of Moser 30-spline shafts,a 30-spline Tru Trac,and just decide on a gear ratio. I would just do a 3:42 and keep all of your drivability. The shafts will need to be custom-ordered. I have a spec sheet for them as I have them made frequently for builds.

 

Thanks,that would be great if you could PM me the info or i can call you at a later date..

 

Decided on 3.73s, anyone have a preference on a ring/pinion manufacturer ? i use to run Zoom in my stuff but i think there looong gone LOL

 

I normally install Motive Performance,in the black & orange box. This is their upper line. Great gear. US Gear is also a good quality gear. They are the only ones that make the 3:55 ratio for the 8.5”. Do NOT confuse that with USA Gear,which is a sister to Yukon.

 

Motive has 2 part numbers for the 373s im guessing the performance is the more expensive one

Part Number: MGR-G885373

Part Number: MGR-GM10-373

 

Need the shock mount area to see if is is a wagon...They normally have lower shock mount brackets and different bump stop brackets. on the lower control area area.

 

Correct

 

or you could pull and axle like Brian said and measure the OD of the bearing

 

I sent Brian a bunch of pic's he verified it as a 71-72 skylark/Gs 8,5 , so would there be a different version for the wagons?

 

Just the axle bearings and seals and the lower shock mount location and upper frame bump stop ...Center is all the same as any other 8.5. If Brian ID ed it I can assure you it is what he said.
Jim
JD

 

Update:
So my Rear guy pulled it apart and it was verified that it had 308 gears , he said everything was in great shape just it was a non-posi , so i went with a traditional Eaton posi unit 28 spline re-used the axles and went with .342's, i also had a spare TA cover from my Gn so we threw that on also, so far so good did some wot pulls feels great, not a huge difference on the highway i didnt feel like i lost that much rpm's on the gear change cruising at 65

 

what is the part number for the 30 spline eaton tru trac? i get confused using eatons own site.

 

thank you! what i dont understand is the eaton link doesnt show that being the correct part number????