and found this from the TCi web page FAQ:

Is there a right way or a wrong way to hook up my vacuum modulator?

Answer: Since the transmission is so dependent upon the modulator to function properly, a good vacuum signal must be transferred from the intake manifold down to the modulator. The best way to insure this is to utilize hard steel line to carry the vacuum signal with approximately three inches (maximum) of rubber hose on each end for the connections. This setup will prevent the hose from cracking or burning in areas that are close to the exhaust system and will also reduce the chances of the hose collapsing onto itself. Most modulators require a minimum of 15 inches of Hg (Mercury) at idle to function properly.


Are there any adjustments that can be made to the modulator?

Answer: Stock factory modulators are pre-set and most are sealed. TCI® StreetFighter® modulator-type transmissions are all equipped with adjustable modulators. By turning the adjusting screw (found in the vacuum nipple) counterclockwise, you will lower the spring pre-load. This will cause earlier shifts. By turning the adjusting screw clockwise and raising the spring pre-load, the shift points will go up. The range of adjustability is only a few mph either way.