I ran mid tens N/A for over 200 passes on a stock block with no block filler. Just a main and velley girdle to hold the parts in. The guy I sold it to is spraying it with 125 shot now. You can do a lot of shit with stock internals but why. What point needs to be proved? Do it right the 1st time and put some good internals in the block. BTW, I sent you a PM a little while ago. I'm saying 331, AFR ot T/F 205's, a well designed cam and a procharger or vortech. Forget about the KB. It's just a name and it's for street cars, not race cars. Good luck!