Bob, I would think that the cam selection would determine the torque curve which is what defines the "drivability" for the engine. The fact that you pushed out to 427 CI on a SBC should not, in itself, result in the engine having to be 2500rpm or better to be street friendly, seems to me. If I'm wrong I'm sure someone will be quick to point out my shortfall in understanding. :LOL::LOL::p:LOL::LOL: