I am in the market for the 8.5 out of a grand national and i found one in the parts thread on this website. I am located in New jersey and the rear is in louisanna and i dont want to spend x amount on the rear and a buttload on shipping to just to have another non posi piece of garbage sitting in my yard. My question is, does anyone know how to identify that this rear is the real deal? Any part #'s or serial #'s on the rear that verify it is a grand national rear? I know that the bolt pattern on the 8.5 is different than the 7.5. Also thanks to the guys on this site i now know the difference between an open rear and a posi. But someone show me what i should be looking for before i drop the cash. Thanks alot.
Grand National Rear
- Thread starter FrIeDTiReS55
- Start date
The 7.5 will have a smaller cover and the 8.5 will be the same as a 1/2 ton truck pick-up or suv.
Hope this picture says it all.
The bolt patterns are the same 5 x 4 3/4 GM the 1978 -1981 were 7/16" 20 thread count and the 1982 -1987 were larger metric studs. Everything else is the same as width spring perch mounts lower and upper mounting points. The 8.5 will have to have a shorter drive shaft by about 3/4" because the pinion is longer and larger diameter than the 7.5 rear. Both take the exact same brakes too.
Hope this picture says it all.
The bolt patterns are the same 5 x 4 3/4 GM the 1978 -1981 were 7/16" 20 thread count and the 1982 -1987 were larger metric studs. Everything else is the same as width spring perch mounts lower and upper mounting points. The 8.5 will have to have a shorter drive shaft by about 3/4" because the pinion is longer and larger diameter than the 7.5 rear. Both take the exact same brakes too.
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for what its worth i used the axle code thats posted and was accurate mine is an 87 rear and is posi i have a th350 and did have to shorten the driveshaft as stated above it bolted in perfectly dont know if you have seen this but here it is .http://www.maliburacing.com also and my personal opinion i wouldnt take the risk if i cant see it in person and inspect it G/Luck
Can you get the casting number off the center section at least. It will be a 6 or 7 digit number on the cast center of the diff housing. We can probably run that becasuse a 7.5 casting will be different then a 8.5 and I have a few housings here were can check it against. Jim
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