I have a 400 small block. It is bored 20 over with flat top pistons, I have a magnum cam from comp cams with .490 in and ex lift. I had a set of heads from a 350 that I sent in and had rebuit ( casting # 458624) they shaved the heads 30 over ported polished and 2 angle valve job.I just told them to give me some performance and thats what they did for me..( this engine was built about 7 years back and used for only 3 summers..well I have it im my firebird with a 700R4 and 390 gears...well it hauls ok....but it still doesnt have that extreme power...I have one of those G-tech meters that measures horsepower and 1/4 mile time...well I can pull 13.89 @ 101 mile/hr....I guess thats fast but to me not fast enough if you figure what I put in my engine....my thought is I am lacking in the heads..seeing as they are low performance truck heads....I have been always thinking about getting a set of vortec heads and use them...but I have been told that with my heads shave and the compression I have I may not gain a thing with the vortec heads...my question is should I replace my heads? or what do I need to get holy crap amounts of power....
thanks in advance