Powered by Mustang Enthusiasts - Call Now (866) 507-3786

Swap Guide For Your Mustang PI (Performance Improved) Components

Created by Taylor Ward
Last Updated 5/17/2021

Swapping your 1994-1998 Mustang heads, cam, and intake manifold for the performance improved (PI) components from the 1999-2004 Mustangs is a great way to pick up an additional 30-40 horsepower.

Viewing this install and using the information shared is subject to the terms set forth here - View the LMR Install Instructions Disclaimer.

FOLLOW: mustang , 94 04 mustang , pi swap

Mustang PI Swap Guide - Mustang PI Swap Guide

Doing a PI swap on your Mustang is a cost-effective way to get more power without having to resort to the high costs of a power adder. The PI heads, cams, and manifold are both easy to find and easy on your wallet.

Mustang PI Head Swap

Parts Needed:
  • 1999-2004 Mustang GT Cylinder Heads
  • Ford Racing Head Changing Kit
  • New Valve Covers If Necessary

The PI heads from the 99-04 Mustangs outflow the 94-98 heads and when paired with the correct PI cams and intake manifold, they deliver a huge increase in horsepower and torque. This will also bump up your compression to 10.5:1. One key factor when sourcing these parts is the difference in Romeo and Windsor heads. A quick way to find out which you have is Romeo has 11 bolts and the Windsor has 13/14 bolts. The Ford Racing head changing kit will include all of the necessary head gaskets, exhaust gaskets, head bolts, and rubber seals you need to make the swap.

Mustang PI Intake Manifold Swap

Parts Needed:
  • 2001-2004 Mustang GT Intake Manifold
  • Intake Manifold Gasket Kit
  • Heater Tube
  • Heater Tube Nipple
  • 2001-2004 Mustang GT Alternator Bracket

The 1994-1998 Mustang intake has a different design than the later 99-04 intake manifold making them incompatible with the PI heads. Luckily, this is easily solved by purchasing a new 99-04 Mustang PI intake manifold from LMR. This new intake features a longer aluminum crossover that extends the hook up to the thermostat housing. This will require a new hose kit and a new alternator bracket, both available at LMR as well.

Mustang PI Cams Swap

Parts Needed:
  • 1999-2004 Mustang GT Camshafts

If your PI heads did not come with the camshafts pre-installed, you will need to source camshafts from 1999-2004 SOHC cams, also known as PI cams. The 1996-1998 camshafts have .482 lift and 204/208 duration while the newer PI cams have a .535 lift and 192/184 duration.

* * *Disclaimer* * *

These are the basic guidelines of the swap. Each swap could be different per application and additional parts may be needed.