Hey guys. Im new to the forum so I apologize in advance if youve heard this a million times but here goes;

I got a screamin deal for a 74 cutlass with a 455 rocket. Its had a few things done to it (ignition, intake, carb, cam) and right now its pushing 280hp and 350lbft torque. I wanna build this thing with my kid and get it to do 12-11 sec 1/4 miles and remain streetable. I dont have much experience with Olds big blocks, so Im wondering what a guy can do to this thing to get it up into that 5-600 hp range? I know you can throw a ton of dough at arbitrary ****, so Id like to ask people who know.......wheres the good money to be spent on this? Should I mess around with the bottom end at all? A cam and heads are a definite. But should i go hydraulic? flat tappet or roller? duration? Valve size? spring tension? Supercharger? carb or efi?

Thanks in advance!