this topic is one of the good reasons i joined...
i my self bought the STEALTH head....i bought them about 2 years ago....i ported them my self.....changed the springs, retainers, lock's and valves....also the valves i used are 3/8 valve stem so i changed the valve guides from 11/32 to 3/8.... also got the right COMETIC head gasket made for that overhang they talked about( the BORE hole) .....my 440 is a 30 over stock steel crank with 9;to 1 comp ratio....
for a long story short,......i made 430HP to the rear wheels on Motor and got 611HP with a 175hp fogger shot to the rear wheels... i hit the track and got very good ET's and MPH.....can't give my times cause i STREET RACE but i have nothing bad to say about the STEALTH HEAD'S .....