A few things I've learned. Shifting earlier than needed on a high torque engine seldom bothers ET much. Shifting late will slow you down. 727 trans takes a few hundred RPM to complete the shift. In testing Turbo Action valvebodys in my stuff it can be 300-600 RPM depending on if its 1/2 or 2/3. The RPM doesn't fall as far on the 2/3 as it does on 1/2. Therefore the 2/3 can be later. If you want to be consistent the shift needs to be close to correct every time. Not using a tach isn't going to get it. We try to predict runs within .005 or closer. Ultimately the quickest acceleration will be measured by highest average G force. For those of you that are running data loggers and that fancy stuff. Read here:
https://www.racepagesdigital.com/tech-why-the-g-meter-is-the-most-important-sensor-for-going-fast/Doug
