From the BIBLE gnttype.org
TCC Lockup
Locking up the torque converter manually has been shown to improve ET's by up to .2 seconds and add 2 MPH to your trap speed in the quarter mile. By activating this switch at the starting line, fluid will travel to the converter forcing lockup once the transmission hits second gear (there is no fluid path to converter while in 1st or reverse.) Yes, this is hard on the converter and transmission, but so is racing in general.
The switch will ground the TCC circuit regardless of ECM request. To install, run a wire from a ground location to one end of the switch and run another wire from the other end of the switch to terminal F on the ALDL connector under the radio pod. (As you are looking at the ALDL connector, terminal F is at the top left.) The easiest way to do the connection is to splice into the wire behind the connector.
Remember to flip the switch to the Off position once you are through the quarter mile to avoid unnecessary lockup, wear-and-tear, etc. With the switch in the Off position, the converter will only lockup when the ECM commands it to lockup. Note that this retains the Brake pedal override.
TCC Defeat
If your torque converter tends to lockup early (dragging down the motor) and you do not have access to EPROM programming, this switch allows you to delay that lockup. (Some transmissions will hit fourth gear very hard if the torque converter is already locked up.) To install, simply cut the purple wire going to the upper brake switch (near the top of the brake pedal arm) and splice in a switch. This tricks the TCC circuit into thinking you have applied the brakes and unlocks the torque converter.
