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.