f150 heads

It's a direct swap from what I recal. New head bolts and head gaskets are probably all that's needed. Your previous intake gaskets are likely reusable, but you won't know until you get them off and inspect them. And assuming the pre-99 4.6L truck engine is the same as the pre-99 4.6L in the passenger vehicles, get ready to start running a steady diet 91-octane fuel. The compression might just shoot up to the 10.2-10.4:1 mark.

Personally though, I think a set of ported PI heads is way overkill for your truck. What you gain in peek horsepower, you'll probably give up in off idle torque. And one thing you're going to want to keep in that 5,500lb monster is all the torque down low you can.