DragRadialRacer

Hey guys new member here. I just picked up an 83 Z with the Southside Machine rear suspension set up. I race in a stock suspension class and I need to put the torque arm back on. Here's the problem, the car has an 8.5 rear, spool, c-clip eliminators, 4.56 gears but no provision for the torque arm mounting. Has anyone fabbed up a mount for the rear of the torque arm and if so do you have any pictures?

Thanks, john

AlkyIROC

It would be cheaper to just install a factory 7.5" back into the car. The GM diff has a cast iron center section. It isn't very easy to weld some sort of mount onto the housing that will be strong enough to take the twisting torque of the diff on the torque arm. To properly weld onto cast iron, it needs to be heated up cherry red before it's welded. That's going to risk causing warpage.

When a mount is installed on a Ford 9", it's a lot easier since the 9" housing is steel and much easier to weld to.

Depending on the rules of your "stock suspension" class, you could buy a bolt-in 12 bolt diff. That way you can use the stock style suspension components and still retain a GM diff unless a Ford diff is allowed. A complete bolt in 12 bolt or 9" diff will run you around $2500.

Sonix

iTrader: (1)

I didn't think you had to heat it up THAT much... but hey, i'm no welder so...

I think MWnova66 was going to run an 8.5" rear, and I would imagine, with a torque arm setup. I know there are others that have used dana44's (meant for 3rd gens), for 8.8", and of course the obvious ford 9" and GM12 bolt.

hey, I want to ask you - how do you have a chev 400 small block, with pontiac heads? They just kinda fit on ? Like SBC and pontiac have the same head bolt spacing and whatnot or is modifications needed? (or was that a typo?) thanks

AlkyIROC

They are SBC heads built by Pontiac specifically designed for racing just like the Big Chief heads are for a BBC.

Although they'll bolt onto a SBC, not much else is considered stock about the head.

DragRadialRacer

Well I don't think the 7.5 would hold up to what I am about to do, so I guess the 12 bolt or 9 inch might have to do, unless I can convince the local tech guy that the SSM set up is a legal alternative. The car 60fts in the 1.30 like it is 406/ 150 shot by the previous owner but the 406 I have has more power, I'm hoping for 1.30's on muscle and drag radials.

The 867 Pontiac heads were eveloped for NASCAR waaaaayyy back and I got a great deal on them so I decided to use them. The rest of the package includes a bow-tie block, .740 solid roller, dart wilson dominator intake and fogger.

Thanks for the input guys!

83 Crossfire TA

iTrader: (2)

You can weld to the cast center section (I believe that it’s actually cast steel, not cast iron since the way they plug weld them would usually cause cast iron to crack, but you can weld to either).

The thing is that the shape of the casting will make it difficult since it will not be as strong as a cold rolled part of the same material so you’d have to get more surface area welded to make it as strong. Personally, if I was going to do it, I’d either make a ring the same shape as the diff cover with some extra tabs on it to attach a TA crossemember or a bracket that loops around where the axle tubes press in and possibly under the housing and around the pinion area of the housing so that you basically have the bracket wrapped around the housing somehow rather then just stuck onto the side