1979 10bolt 8.5" Rear bolt into GN?

V6UnderPressure

The Artist FKA Scott4DMny
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May 27, 2001
Are the older 10bolt rears in the regals etc. similar to the GN 10bolts? I know the flange for the backing plates are different, but what about track width or anything else pertaining to the rear (shock mounts, trailing arm mounts, spring perches, etc) Thanks all!
 
79 has the same rear as the later cars. 77 and earlier would have an 8.5. I believe they are wider and require different upper control arms for the swap.
 
Thanks. The 79 has a square flange though doesnt it where the backing plate bolts up? Or am I mistaken?
 
V6UnderPressure said:
Are the older 10bolt rears in the regals etc. similar to the GN 10bolts? I know the flange for the backing plates are different, but what about track width or anything else pertaining to the rear (shock mounts, trailing arm mounts, spring perches, etc) Thanks all!

forcefed3.8's is correct, 77 and older cars were 8.5's. they will require special upper arms, and if I'm not mistaken they are about 1.5 inches wider on each side then 78-88 G body's
 
I know alot of people running the LS1 or LT1 brake swap cut the top "triangle" section off the flange on each side of the rear end to make it square like the others. The question I have and I know its kinda oddball, is what other years of 8.5" rears have the square flanges? I know there are camaro 10-bolts out there etc.
 
V6UnderPressure said:
I know alot of people running the LS1 or LT1 brake swap cut the top "triangle" section off the flange on each side of the rear end to make it square like the others. The question I have and I know its kinda oddball, is what other years of 8.5" rears have the square flanges? I know there are camaro 10-bolts out there etc.

The older A body GM's I believe also used the square flange, however those particular 10 bolt rears were 8.2 ring gears. Doesn't matter Chevy or BOP. The differences with the BOP 10 bolts in A bodies is they use bolt in axles instead of C clips, and the carrier assembly differs from Chevy version. With good aftermarket axles and posi's these rears can handle a good bit of abuse.
 
the 78-88 A/G bodies, 80's S trucks, and 80's F bodies are the only applications for a solid axle that don't use the 4 bolt flange.
the BOP 8.5 axles with pressed on bearings in some 73-80something A and B bodies have the 4 bolt pattern, but it's different.
as far as bolting an 8.5 out of something like a 73-77 A body or 77-96 B body (they are pretty much the same chassis as each other..), it won't happen without a lot of work. while the mounts for the lower control arms, springs, and shock mounts can be cut off and transferred over, the bosses for the upper control arms are cast in totally different places and at different angles on the center section.
you used to be able to buy conversion upper arms for putting a 12 bolt out of a 64-72 A body, but i don't know if they are available any more.

so, to summarize- the cheapest and easiest way to put an 8.5 in a G body is to find one out of an 84-87 GN, T Type, or 442. it will cost more up front, but it bolts right in and you save a ton by not needing to do any fab work..
 
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