I found after switching to the 4.10's in my new differential the somewhat crappy shift points in my 700R4 became really crappy. I was in third gear at 25 mph and OD before 4'th. I read all about the calibration kits being back magic and total trial and error, but decided to try it anyway. I bought the B&M kit from Summit (I bet they are really all the same).

I bought a second governor off Ebay and gave it a try. It has secondary 'C' weights and two different springs, not sure of the color. Everything said to change one thing at a a time, but I was having my speedo gear set changed today and the guy at the shop was willing to swap it out for and extra $20. I put in the #1 weight and orange spring on one side and the #2 weight and yellow spring on the other.

What a difference! Shift points are much higher now and spread apart as they should be. It goes into 4'th around 45 now, and OD about 50. I can finally put the car in D and drive it, not manually selecting gears all the time. Very cool and a lot more fun to drive. After 13 months, this car finally drives like it should. Guess my point is don't be afraid of governor calibrating, it is not hard and can work out first time.

Tim

 

Did you check how it shifts at wot?

 

The tach I have is not very well placed for observing during high RPM shifting... ;-) Feels like the WOT is around 4500-5000 rpm. Given this car is not really a racer, but a pro touring type build, I'm happy with the result. I'll characterize the shift point vs. load at some time down the road, since I can not hold the A.R. engineer inside me at bay forever....

Tim