I tested the 68 440 mani, the CH4B and the TM7 at the track in 74 on a 426 street wedge with a small cam and 11" converter. The stock mani 13.37 the CH4B 13.34 and the TM7 12.98. This car was very repeatable within a couple of hundredths and I bracket raced it while I was building a new engine for my main race car.
Quite a jump on that TM7
Very motor combo dependent.
Of the Original Poster has a stock 440 with smaller than the factory HP 375 HP cam specs: 268/284 Duration, 0.450"/0.458" lift, 46 degrees overlap (115 LSA), installed at 113 Intake CL. And street gears like 3.23 or smaller.... the smaller Performer should be fine.
Even with that stock 383/440 HP cam the Performer RPM might be an improvement over the Performer.
