Congrats to member Scampin
Currently, there are no BB A body guys running. There is a “383” A body close to being finished. You would need to run the A body 383 exhaust manifolds to be legal. You might be able to run whichever fits, C or B manifold if you ask. They are better, but with the cost and scarcity of original 383 manifolds they might let you run them. Honestly, not sure a BB in an A body in FAST is going to be better that a small block. You still have to run a single 4 barrel, you don’t get much better head flow, no 904, but you do get about 100 lbs of nose weight you can’t get rid of.