i think the valves are a completly different animal frank, because at that point the other cylinders dont affect its individual flow as much as when all the pulses mix together at the collector, im sure you are correct that changing all the paramiters would be best ,i just keep thinking that by changing the exaust it could make an improvment, because at low rpm's not that much air would be tring to get past the valves ,, but i have only modified v-8 carburated cars so i will defer to the more modern builders advice,i have seen big changes in v-8 cars depending on header primary diameter/length, and collector diameter/length, some of those cars highly modified, some stock,,but all 302+ cubes
