Frame or chassis options for A bodies
Being I have owned Tbar cars and while I fully agree with 72 bluNblu that they do work, honestly in my opinion that are not as fast as a good coil over kit. One only needs to look at vintage porsche's to see that if one wants to go fast, they all convert to coil overs.
With all due respect, I think that is a little bit of an oversimplification and not an apples to apples comparison.
I find it hard to believe that a Porsche TB suspension has many similarities to an A-Body TB suspension, besides a long straight spring. Just a thought, but if the aftermarket coilovers on a Porches also corrected some geometry inadequacies, then it might have less to do with the torsion bar and more to do with a different suspension design.
For example, the early Camaro has a horrible front suspension design that requires huge spring rates to get the required wheel rate. If a new coilover kit relocates the lower shock mount so the spring is more effective, the car suddenly turns faster lap times, but it might be less about the "magical" coil over and more about a better design.
Can't argue that losing the TB gains room, but beyond that I don't see what the advantage is.
And don't miss that most of the aftermarket kits I've looked at don't seem to have the support for the lower control arm that the factory suspension gives. Not much bracing and no triangulation so when the wheel hits a bump the lower ball joint moves backwards. Maybe it's no better than a factory setup with a worn out strut rod bushing, but it's at least designed better and just needs to be upgraded to be executed effectively. The pictures above are a decent example of this, with a long control arm and a relatively narrow mount at the pivot point. Lot's of leverage there to move the LBJ backwards and forwards and disrupt the handling. Maybe it is beefy enough for this, but it is working against the laws of physics, rather than with them.
I'm struggling to think of a fast A-Body with coilovers...maybe Wracks? But there are 3 listed below that are TB and leaf spring cars, and the Green Brick isn't even one of them.
But you don't need it. lilcuda's '68 Valiant has lapped portland international raceway as fast a C06, hitting 160mph down the straight, it's a torsion bar and leafs car. Tomswheels ran the Goodguys autox faster than some $150k Camaro with his '69 cuda convertible, and he was still running $14 Gabriel shocks. I'm guessing the $150k Camaro was a bit easier to drive though. And his Valiant is faster than that and still a torsion bar and leafs car, it won SCCA CAM events, finished 2nd to M. Pozzi at San Diego, 5th in the CAM nationals west, etc.
Heck I heard Tom was selling his car, you could buy his for less than it would cost to go to a full chassis. Or to even build his car...
I wonder what Tom would have done at the CAM nationals with the motor out of lilcuda's car. Pretty sure he was down significant horsepower to most of the people he ran against, and still finished 5th.
Shame he is selling it. Still don't agree with the reasoning, but it's his car and he can do with it as he wishes...