I run the M1 single plane on an Ed headed 496 B stroker in a '70E with 5 speed. EFI. 243@.50" cam and 3.23 rear. I am very happy with it plenty of torque for normal driving at 2000 RPM... even in overdrive. If I don't completely stomp it it will pull clean from 1400 RPM. It is a bit tall... just fits under my flat hood with short EFI throttle body and a moderate drop air cleaner.