GM 12 Bolt Rear End to G-Body

[gnvair]

FB market place and swap meets man circle track people constantly sell them just make sure they are not bent and make sure they are not offset

Finding deals with good 31 spline carriers and good axles is about as common as finding a Ferrari for $500. Sorry if it was as easy as you say more people would be doing it. Maybe you should start picking up those deals and adding the control arm brackets and spring perches and reselling them on here.

 

[39F]

Finding deals with good 31 spline carriers and good axles is about as common as finding a Ferrari for $500. Sorry if it was as easy as you say more people would be doing it. Maybe you should start picking up those deals and adding the control arm brackets and spring perches and reselling them on here.

I got 7 carriers I got lucky with one and it had 410 rest had 350 270s in them all from swap meets the 28 spline ones I take and use a reamer to make it the same size as 31 ,I'm poor I can't afford to buy expensive parts lol ,what's kinda cool about the full floaters the axles are cheap and you can narrow them whatever size you want

 

[pontiacgp]

I got 7 carriers I got lucky with one and it had 410 rest had 350 270s in them all from swap meets the 28 spline ones I take and use a reamer to make it the same size as 31 ,I'm poor I can't afford to buy expensive parts lol ,what's kinda cool about the full floaters the axles are cheap and you can narrow them whatever size you want

the splines in the 9" axles are machined, the GM axles are cold rolled so you can't modify the GM axle

 

[39F]

the splines in the 9" axles are machined, the GM axles are cold rolled so you can't modify the GM axle

I'm talking about the carrier how the 28s are smaller ,yea you can't modify the shaft themselves really unless you got a guy with a spline cutter

 

[gnvair]

I wouldn't want to modify a stock shaft anyways. Having worked in a performance shop I can tell you those stock Ford axles shatter like glass when they break. They make a terrible mess. If it was something that was being driven on a sticky tire or raced I would always go for a quality after market axle. I would also save the heavy full floating axles for the truck guys. A full floating hub is one heavy SOB.

 

[Macguyver]

Hi everyone,

I know this has been posted on here and I have searched but just want to make sure i have the correct info for what I need.

I have a 78 Cutlass Supreme with the GM 7.5 Rear end. I know they do not hold up at all as soon as some power and sticky tires are added to the mix.

I was browsing around and found a used GM 12 bolt rear end from get this, a 1969 Cutlass. The guy wants 400 Canuck bucks for it so it seems like a great deal all things considered. I know there are other options for a rear end as well (GM 8.5 from a Grand National, 442 or Turbo Buick, Ford 8.8 from a Foxbody or SN95, Ford 9.) But they all require some work and fabrication to swap over.

Now, from what i have gathered on here, this particular axle is approximately 61 3/4" from axle face to axle face (a few inches wider than a stock 7.5), a different bolt pattern, and that for the swap to work, new adjustable upper control arms and the spherical bushings in the diff. housing are needed, the lower control arm mounts on the axle need to be relocated and new adjustable lower control arms used, and coil spring perches and shock absorber mounts relocated? Is this in the ball park for what needs to be done? And would using the dimensions and geometry from the stock 7.5 be the way to get everything just mint on this 12 bolt? Or can it be swapped in for less work than needed above?
The welding and fab is no issue for me!

I would more than likely grab a 12 bolt kit from one of the sponsors/shops on here and have at er. And please dont say to buy a brand new made to fit rearend. I would love to be able to buy a G-Body ready unit from Moser, Currie, etc., but they are out of the budget completely (Especially with exchange and shipping) and for what i want to do with this car (A solid, well built and fun street machine)

Thanks again everyone. Such a great community on here! 🍻👍😎

So what did you end up doing for a rearend?