i am currently driving a 1993 gmc sierra 1500 regular cab long box 2 wheel drive with a 305 CI in it. I have recentley bought a 350 CI TBI used. It would be nice if it was sitting at about 400 hp, how can i get it there? what pistons would you go with? what camshaft ratio? should i get new heads or machine the old ones? How do i go about building a 400hp motor?