I remember Paul Rossi and some other SO CA six pack NHRA SS racers in the early to mid 1080 saying they shifted there motors sat or close to 5500 RPM with the two piece bolt together Weiand six pack intake with O69J converters
Paul was testing T/A converters at Orange county on a Wednesday night before the first divisional race over in Phoenix in 1979 later that week, he would leave at a idle and pull the front tires way up and long in first gear in his 1971 Challenger
My pump gas 400 stroker motor with a stock low deck six pack intake with stock type 440 vacuum carbs like to be shifted above 7000 RPM to make the car goes as fast as it would that solid roller cam was 260@.050 on the intake lobes with .420 lobe lift and it had 266@.050 on the exhaust with .409 lobe lift ground on a 108 LSA installed 1 to 2 degrees advance depending on which lobes I check
I dyno tested that motor on three different brands of engine dyno in three different towns, Ontario,CA on DTS engine dyno in Madras, OR. on a Studka brand engine dyno and in Klamath Falls, OR at 4300 Ft elevation on a new(at that time) DTS the last time. It would make peak torque either at 4500 or 4600 rpm with peak HP at 5500 or 5600 RPM regardless of which brand dyno or at what elevation I had two different sets of heads on that motor with the six pack, I later swapped the heads to a set of Indy SR M.W. ports with a Indy 400-3 intake with a 1050 CFM Holley Dominator carb, which made some more HP and torque at a lot higher RPM with the same cam. Those changes pick the car up around .25 ET and 8 MPH