alternate 3rd members

[DrRansom442]

OK so I can't weld. Also I can not seem to find a sutiable replacement for my factory 7.5". It aint broke (yet I haven't gotten my mild 350/200-4r in). I've been eyeing up differentials, and it seems everyone wants $700 and up for open 8.5" 10 bolts. Any 12 bolts or 9" for G-bodies seems you can buy new for what they want used. So this leads me to ask ... are thre any other cars that 3rd members can be adapted to teh G-bodies with little to no fuss. Preferibly bolt-in. I've heard that A-bodies fit but are wider. I've heard the same about late model B-bodies. Help a fellow Olds brother out ... let me know what else I should be looking at

 

[joe_padavano]

OK so I can't weld. Also I can not seem to find a sutiable replacement for my factory 7.5". It aint broke (yet I haven't gotten my mild 350/200-4r in). I've been eyeing up differentials, and it seems everyone wants $700 and up for open 8.5" 10 bolts. Any 12 bolts or 9" for G-bodies seems you can buy new for what they want used. So this leads me to ask ... are thre any other cars that 3rd members can be adapted to teh G-bodies with little to no fuss. Preferibly bolt-in. I've heard that A-bodies fit but are wider. I've heard the same about late model B-bodies. Help a fellow Olds brother out ... let me know what else I should be looking at

Here's an economics lesson. The bolt-in 8.5" axles sell for what they do because there is no other bolt-in alternative.

 

[DrRansom442]

OK so I can't weld. Also I can not seem to find a sutiable replacement for my factory 7.5". It aint broke (yet I haven't gotten my mild 350/200-4r in). I've been eyeing up differentials, and it seems everyone wants $700 and up for open 8.5" 10 bolts. Any 12 bolts or 9" for G-bodies seems you can buy new for what they want used. So this leads me to ask ... are thre any other cars that 3rd members can be adapted to teh G-bodies with little to no fuss. Preferibly bolt-in. I've heard that A-bodies fit but are wider. I've heard the same about late model B-bodies. Help a fellow Olds brother out ... let me know what else I should be looking at

Here's an economics lesson. The bolt-in 8.5" axles sell for what they do because there is no other bolt-in alternative.

So these don't work? or am I missing something?

Correct angle to attach to the G-body chassis!
UMI Performance 12-bolt swap adjustable upper control arms are designed to bolt a 1964-72 GM A-body 10-bolt or 12-bolt rear-end into a 1978-88 GM G-body. These control arms are a must any time this swap is being completed. Using factory control arms will cause drastic rear-end bind and an incorrect driveline angle, which leads to traction loss, vibrations, and unsafe handling. UMI Performance 12-bolt swap adjustable upper control arms allow for easy on-car adjustability to set the correct pinion angle and make installation adjustments if needed. Adjustments are made using an aircraft-quality, 4140 chromemoly, heat-treated adjuster and spherical bearing rod end. The rod end allows the rear-end free movement when high-handling, autocross, or road racing is a concern; it also works great as a drag racing item by eliminating rear-end bind. These upper control arms feature TIG-welded construction and 4140 chromemoly tube adapters.

 

[dan2286]

I believe the 12 bolt is too wide, that is why it is technically not "bolt in".

 

[DrRansom442]

I believe the 12 bolt is too wide, that is why it is technically not "bolt in".

well I knew there was a width issue ... like 1.5" either side I think, but I sure can find 12 bolts more plentiful (and cheaper than an 8.5) ... 12 bolt will also take more abuse. I swear I had read that late B-bodies can be adapted too. Again is width the primary issue?

 

[88ss408]

every B-body i have ever seen has a 7.5 also so why would you put the same rear that is too wide ??

 

[jrm81bu]

9c1's have the 8.5, at least i think thats the code. Cop cars do anyway.

 

[yourownself]

right now i'm looking into pulling an s-10 axle and having the mounts welded on.
i've done a fair amount of research and am having a hard time finding out if one is the right width, so once it gets a little warmer, i'm hitting a few junkyards with a tape measure, and i'm gonna pick me a winner!

it seems to me that car guys are a-scared to MAKE an axle fit!
i can't tell you how many guys i know with explorer axles under a jeep, or guys that will pull a 9 inch out of a truck, and make it fit a wrangler!
it's just a matter of putting on some spring perches, and fabbing up some control arm mounts!

the only thing i really don't want to do is shorten the axle, because if i bust a shaft, i want to be able to pick 'em up out of a junk yard, rather than custom order them from currie or moser.

 

[Blake442]

8.5's bring the money they do because they save the expense of making something else work. Convienience costs money. Plain and simple. Sure, you can find a 12 bolt out of some car, and then spend spend spend to make it fit...

4x4's are easier candidates for creativity because a leaf spring axle is a much simpler swap.

'94-'96 Impala SS's and Caprice 9C1's have an 8.5" rear.
Rear disc brakes too.
But they are also a 5x5 bolt pattern, so you'd either need to change axles, redrill your axles, or swap to a 5x5 wheel. Not to mention that it's too wide to begin with.... See why the 8.5 looks better and better?

If I was putting up the coin for a new rear end, I'd get a complete G-body 12-bolt from Moser and call it a day.

 

[DrRansom442]

right now i'm looking into pulling an s-10 axle and having the mounts welded on.
i've done a fair amount of research and am having a hard time finding out if one is the right width, so once it gets a little warmer, i'm hitting a few junkyards with a tape measure, and i'm gonna pick me a winner!

it seems to me that car guys are a-scared to MAKE an axle fit!
i can't tell you how many guys i know with explorer axles under a jeep, or guys that will pull a 9 inch out of a truck, and make it fit a wrangler!
it's just a matter of putting on some spring perches, and fabbing up some control arm mounts!

the only thing i really don't want to do is shorten the axle, because if i bust a shaft, i want to be able to pick 'em up out of a junk yard, rather than custom order them from currie or moser.

Since most Jeeps still use leaf springs .... That makes them pretty darn easy to swap rearends ... your mount is a U-bolt. I was looking for something either direct bolt in or bolt in with adapters because (as previously stated) I do not have the capacities to fabricate.
"it's just a matter of putting on some spring perches, and fabbing up some control arm mounts!" This isn't simple - one has be be VERY precise or binding/damage WILL occur. I am not in a huge hurry here. I don't even have my engine and transmission in the car ... I am just worried the factory 7.5" isn't going to live long behind something other than the 260.