Lets talk about the B body first....
B Body are hard because Mopar no longer sells the old P5249156 .840 bars. I would look and see what the after market has. B Body's can be made to work very well but the learning curve is long. You have to have a very consistent engine,trans and rear suspension to be able to fine tune the front suspension. Trying to do this on a fresh chassis is hard to say the least.

Here is a picture of a customer of mine. Chuck Steinbeck has ran this car in D, E and F and has done very well but 10lbs and a 1/2 turn on his shocks makes a big difference. IF I remember correctly these are the some .840 bars.