It has been my experience that shifting on time is more consistent for me. Someone earlier in the tread had a digital delay shift timer. That's what I use. Every 3 speed transmission braket car I ever had ran quicker if you short shift the 1-2 shift. We shift 1-2 at 1.65 seconds which is 6400 rpm for us and 2-3 at 3.80 seconds which is 6800 for us. Plus with the digital delay timer you can start the timer by rpm or trans brake release.