I bought a rear-end off a guy at work for 50$. He said it is the original out of an '84 chevy pick-up LWB. How do I know for sure if it is an 8.5 or an 8.2? Some one had put a posi unit in it and I plan on using synthetic gear oil after I put it back together. Do i have to change out the clutch plates on the posi? It has 28 spline axles in it. Can I upgrade to 30 spline by just changeing the spider kit and axles?  

GM stop building the 8.2 inch in 71 so I guess you are safe, but I would double check with a rearend shop to be sure.  

thanx for the info.  

can anybody tell me which one this one is? it's stock in my '70 nova. the only numbers i can find on it are "12345". i dont think that will help much. i've read all of the articles on the internet that come up when you google it, and i still cant figure out which one it is. the oil you see on it is from the motor.

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i just wanna hit this computer with a bat sometimes







 

Its pretty safe to say that its a 8.5,GM put those in full-size trucks,elcamino's(my 76 had a 8.5 28 spline)and some fullsize cars.Upgrading to a 30 spline would require changing all the guts,seals ect.My camino had the same rearend you got,I installed a spool and a 4:11 gear,ran a 26/10.50 slick and ran mid 11's with a 1:654 60ft with no problems,never broke it.