Gearing and shifting 4 speed at the track

318willrun said
I agree. IF you had only changed the gear, you'd saw a small difference with your set up. But you did a massive change to the entire car.

I did a swap with a mild 360 I went from 4.30's down to 3.91's. My E.T. and MPH stayed exactly the same.

Then the RPM at crossing went down and you had too much gear to begin with. It's a math calculation. Stroke length has nothing to do with it. It's RPM, tire diameter and gear ratio.