452 heads

timing....

yes the flow is there on the bench, but does/will the cam chosen allow enough of it in to get whats needed into the combustion chamber, thats what is being said here.

if these heads peak at .5-.550 lift...i would pick a cam that opens the valve around .575....dependent upon wether or not they back up real bad immediately after or not ...if thats too much cam for u...then at least get an actual .530-.540 lift at valve

if u only just touch the 240-250 cfm lift range, ull need more duration to insure the goals reached, imo...go lil more and it's less....lol so more lift can be less cam when it comes to manners relevant to fast rate lobes. jmo