hello there and thankyou for all the help! i am already running the shumackers, have done for several years since did the conversion, my thoughts were these really, if i can get say 400 to 450 hp with my engine overhauled using my heads..... and the shumackers only really work to say 450hp due to their size wouldnt it be a waste of money going ali heads that yes have a potential to flow to 600 or whatever only to be let down by the shumackers? many thanks nathan.
