I have a 305 and right now my tranny shifts at 4500 when i really lay into it.I am doing all kinds of things to my motor that will make power up to 5500 rpm at least maybe even 6000 rpm.How would i get my tranny to shift at like 5500 instead of 4500.I already have the tv cable adjusted to the highest shift.would a shift kit fix this?? thanks for the help

Brandon

 

A shift kit is a good idea but usually won't change the wot shift points that much.
To alter the wot shift points you need to install lighter inner weights in the governor. There are several ways to do this. The easiest may be to order the B&M governor calibration kit, jegs and summit have it. If you have some spare governors you can experiment with grinding the weights and reinstalling them with #6 finishing nails.
Change the springs to alter part throttle shift points below approx. 40 mph.

I went to a trans repair shop and got a free bucket of governors, some are worn out but they have usable weights and springs.