I read this thread a while back, I just decided to come back and give my 2c. I don't remember what other points have been made yet though.
I haven't had much (read: any) experience with E bodies except whats online, but I have taken an interest in suspension and handling.
Anyway, to the best of my knowledge, if maximum lateral gees is your aim, then one of the most important starting points for the car is where the center of gravity is, since it isn't going to change very easily. For maximum lateral gees, you would want a low one to minimise lateral load transfer, but for straight line acceleration, a high CG will get more load on the rears, so it's a trade off. I don't know where on a barracuda the CG is so I can't make much of a conclusion, but just compare its dimensions to another car and make your judgment. By the way, if anyone has a pair of 1000 ish pound scales and some way of lifting the front end of the car, I can walk you through a procedure to find the height of the CG, and off course where it is front to back. The CG position also defines how much weight is on each wheel when the car is at rest (Ie: weight distribution), which you all know is important.
Another thing is the wheelbase and track. Wheelbase is important because the shorter the wheelbase, the more weight is transferred for a given acceleration. Weight transfer is basically directly proportional to the length of the wheelbase, so the couple inches between a cuda and a challenger won't make a huge difference, but a 10 inch or so difference will be very much noticeable. So a short wheelbase will give you more straight line acceleration. You want a large track, on the other hand, since lateral load transfer isn't very good for traction, and is proportional to track in the same way as longitudinal weight transfer is proportional to wheelbase.
The live rear axle on an E body is definitely bad. If you had a dead smooth track it wouldn't be so nasty, since unsprung weight is such a huge issue with a live rear axle, but god knows there aren't many of those around. Even with a perfectly smooth track, a live rear axle has a nasty habit of causing load to transfer from one wheel to the other. That is bad for traction, as usual, and while it can be remedied for a given torque, if that torque changes, ie you change gear or take the throttle off or drop or add some revs, the remedy will no longer work (to the best of my knowledge).
I would also worry about chassis stiffness, because chances are the front will be very slide out happy as you go around a corner with throttle off, and the simplest solution to that is probably adding some rear roll hardness, but that won't be all that helpful unless the chassis is stiff enough to transfer the hardness through.
Those are probably the main things I would be worried about if I was thinking about racing an E body. I don't know numbers for the E body, but I'm sure a good old guesstimate from you guys with more experience, would suffice.
Oh, and again, if anyone wants to put the rear of their car on a scale and jack up the front, I can walk you through a procedure to find the position of the center of gravity. I'm working on a simulator for vehicular handling, and some good test figures would be nice. I can even give some info back (although it will probably be pretty useless at this stage, except for novelties sake)