Join Date: Nov 2002
Location: Over At the Frankenstein Place
The Explorer Engine is what is commonly referred to as a PI Engine. Better Cam, Better Intake Manifold and on a Non-PI block, the heads will increase your compression ratio for a slight bump in power. On your 94 the Explorer Engine would be a good upgrade, because the 94/95 Heads are crap, so you can't upgrade to the PI cam without a lot of work, unless you want to swap the PI Heads, which is going to require a lot of 96/97 T-Bird parts. The Search feature should have the answers you're looking for..
search: PI Head Swap or Explorer Swap for details on either.