97cobradude92

would navi heads work on my 97 if so what the hp+????

crysalis_01

They should fit, they have a much larger intake port volume than 4.6L castings but relatively small exhaust port for the size of the head. And because of the larger intake port size, you're left with a slim selection of intakes to choose from when swapped onto a 4.6, which is the biggest down side to doing this.

You're probably better off finding a set of ‘03+ Aviator, Marauder, Cobra, or Mach 1 heads if you're looking for a "better" design.

Of course this is all in the 4v head info sticky. It's a "lengthy" read but is full of excellent information.