What rpm do you shift at?????

darndart said
My old 10.5:1 340 with MP 557 cam, Ported J heads, M1 single plane, I shifted at 6200. I tried higher, all the way up to 6800, but it didn't help my ET, so I stayed at 6200!

Exactly. Shift point is very build dependent. My combo wanted a 7800/8000 shift point and that is where it got it's best ET.

If I shifted at 6200 I would be keeping the car way under the curve for the entire run and my ET would have suffered.