Professional Products LT1 Throttle Body - Waiting To Inhale

Now you're ready to transfer the IAC manifold to the new throttle body. (Be sure to use the fresh gasket that came with the kit.) With that done, install the TPS and insulator.

The finished product should look something like this.

To install the new throttle body on the car, simply reverse the teardown process. Before reattaching the air-intake tract, have a friend sit in the car and, with the engine off, fully depress the gas pedal. Verify that the throttle blades open completely, as shown above.

Reinstall the intake tract, reattaching the AIR and Opti-vent tubes along the way.

You may need to use a flathead screwdriver to gently stretch the intake bellows over the larger-than-stock throttle-body opening. Tighten the clamp securing the bellows to the throttle body, then fire up the car and check for air leaks. The engine may idle a bit roughly for a few moments, as the ECM adjusts to the additional airflow.

Here's a look at the engine with the new throttle body installed. Too bad the rest of the top-end hardware doesn't look this nice.

Having verified that our installation was leak free, AntiVenom honcho Greg Lovell strapped the car to the shop's in-house chassis dyno and made a pair of pulls. While the larger throttle body didn't add to our '96 coupe's peak output, it did boost horsepower by as much as 6 between 5,000 and 6,000 rpm. A post-install test drive also revealed throttle tip-in to be noticeably sharper, giving the car a more responsive feel in everyday driving. Perhaps most important, the extra airflow capacity offered by the 52mm throttle bores should help optimize the performance of the head-and-cam kit we have planned for the near future. More on that in an upcoming issue.