The GM's Tuned Port Injection consists of an upper intake commonly known as the "Plenum", Runners (LTR or Long Tube Runner), and a Lower Intake known as the "Base". The Plenum is designed to act as a reservoir to feed the runners. The runners which are tubes feeding air to each cylinder are specifically designed to produce a torque curve that is ideal for low end stump pulling torque. The design of the tubes takes advantage of the induction wave generated with the opening and closing of the intake valve. This wave travels from the valve back to the entrance of the tube, where a reverse wave is created, it then travels back to the valve, pushing air with it as it travels, thus creating a "ramming effect". This effect increases volumetric efficiency in the RPM range for which the ports were tuned for.

Tuned Port Injection in contrast to its brother the LT1 can produce better low end torque but at the expense of top end power which the latter are known for. So even though the LT1 induction systems produce higher "market horsepower" numbers, the TPI powered cars can hold their own when it comes to launching. So  "torque wins races, horsepower sells cars".