Ok so i have stock holley heads 1.94 and 1.6 valve (intake and exhaust) they are stock i believe at .500 lift flow is 225 and 160 cfm. my question is what to do? is it worth getting these things ported and polished? btw i have nitrous valve installed for the exhaust. the shop that did it cut down the valve stem in the exhaust runner claiming 5 cfm more flow. i never heard of it so i posted stock flows. if there claim is true then i guess 165 cfm on the exhaust. or do i buy a new set. my plans are to get a 408 stroker built. i was told these heads would limit that engine to 475 hp. which to me is nice considering i believe that is more hp then mu current 351W with a 100hp shot of juice is making. what are your thoughts?