Since no one has responded to this question, what are you trying to do? get it to shift later or earlier?
In the old days when we wanted to up the shift points on a 400 we used to drill (4) 1/4" hole in the swing weights on the gov. this lightened them up making the shift points higher on acceleration.
Of course with todays and yesteryears modified 400's the gov. is eliminated/pluged.
Zip.