70 Chevelle 12 bolt fit a GN?

[daviss]

A buddy's dad has a GM 12 bolt that he swapped out for a 9" when he back-halfed his race car. It's from a 70 Chevelle. Will it work, and if not, why?

 

[Red Regal T]

I don't think it will. All the purches have to line up. Probably ears on rear are not the proper angle to line up and the outer attachments would have to be the same as a Regal. Never saw a post of anyone who has attempted it. Maybe someone else will know for sure.

 

[GNVAIR]

It will fit, but you will need a special set of upper control arms to make up for the angle difference on the mounting ears.
SSM and HP Motorsports each make/made a set.
You will also need to cut off the coil spring perches and weld on the G body style perches.
The 64-72 A bodies rear ends are significantly wider so you will also have to take that into consideration with your wheel selection. If you go to www.maliburacing.com you will find many guys who have done this swap.

 

[Red Regal T]

Goes to show ya.......if there's a will, there's a way. Thanks GNVAIR!

 

[daviss]

Excellent. I forgot to mention that it is narrowed 4" so that's a start. That should at least get in the realm of wheel backspacing to make up any difference. Sounds like a good winter project. Anyone interested in the results if I go through with it?

Thanks for the input.

 

[turbofish38]

Originally posted by daviss
Excellent. I forgot to mention that it is narrowed 4" so that's a start. That should at least get in the realm of wheel backspacing to make up any difference. Sounds like a good winter project. Anyone interested in the results if I go through with it?

Thanks for the input.

Stupid question. If it is narrowed than that would change the location of the lower arms wouldn't it?

I have a 8.5" B-O style 10 bolt under my GN using the HP Motorsports kit and the lower arms are slightly shorter, not offset like the upper ones. The lower arm brackets are out at the axle flanges so narrowing the axle would bring those brackets in and out of alignment. Does your 12-bolt still use the stock suspension or is it a race type set up for a 4-link and coil overs or some other set up?

Oh, I forgot to add my axle is from a 72 Buick Skylark which should be the same length as the 70 Chevelle.

 

[daviss]

It still has all the original perches. They were moved back to the original location. So only the axle tubes are different.

Perhaps I should go measure everything

Thanks for the input.

 

[GNVAIR]

I put a 12 bolt from a 70 Monte Carlo under a 78 Malibu I had years ago. You definitely have to swap the coil spring perches. At the time I shortened and redrilled the upper control arms. The lower arms bolted right up. I had to tweak the lower shock mounting studs so the shocks wouldnt rub the larger axle tubes.
Talk to the guys over at Malibu Racing. Many have done this swap.

 

[turbofish38]

Yes,to do this you will have to cut off the spring perches and weld new ones to the top of the tubes and you have to weld new lower shock mount studs as you cant use the stock location as they are twisted in a slightly different angle. The lower arms are a little shorter, I cant remember but it is not much. If anything the stock arms will just change the pinion angle slightly. Using the stock upper arms will create a bind causing some problems, mostly with poor 60' times. IMO buy the HP kit to keep the hassles to a minimum. Also I dont remember the exact numbers but I think the 72 rear was only 3" wider than the TR rear.