The Stovebolt Site Forums The Shop Area Driveline power glide

if the throttle linkage pushes on the rod as the throttle is opened, then shorten the rod and it should shift sooner.

If the throttle linkage pulls on the rod as the throttle is opened then the rod will need to be made a bit longer.

I don't remember if the throttle linkage pushes or pulls on the rod to the transmission.

Also, make sure the vacuum supply to the modulator valve is ample. Make sure there aren't any holes in the line to the modulator, and make sure there is vacuum at the modulator.

If you pull the vacuum hose off the modulator and transmission fluid comes out, even a small amount, replace the modulator.