I read before that a 318 can have valve interference with the cylinder wall if the valve is too large? My 318 has been bored 30 over and I wanted to know if a 2.15 intake valve would be too big. Also, is a 300 cfm flow too much for a street engine? The engine has the kb167s in plus a 274 retro roller cam. I want a nice street engine so I want some low end power, not the top end.