I take it your using the engine only and not the TBI set up? If so you will easily make 350hp with a cam and head change. You can achieve what you want with the stock TBI heads but they will probably be limited/struggling to make 350hp and by the time you got them work on you could of got you a better set of heads to reach you up to 400 hp. TBI heads SUCK ,or really dont suck , air flow is restricted. I use the TBI set up for staying at low rpm and low end torque, I got a heavy vehicle that sees a lot of idle time and probably never above 4000 RPM. If you just want to start your build with a "TBI" short block , the TBI really means nothing. Its a great SBC block.