Heads

It depends alot on the application, if you plan on putting a power adder on, then the heads will pick up some good numbers. For n/a I think you get around 30hp or so, I could be wrong but seems like its around there. If you are going to do heads I would suggest doing cams as well. One thing to keep in mind when doing heads is to be true to what you are going to be using them for. If your going to keep the stock bottom end and no power adder dont get the biggest flowing head numbers because they wont be as good as a smaller port job because you will lose air velocity. I was quoted around 4000 for a head port and cams from a local speed shop I deal with. Hope this helps.

Ya I agree with you on the change of heart, just made the same decision myself. Sadly if you want 400 hp to the tire your most likely going to have to stroke the engine. I have been checking out the FRPP BOSS Modular block for my build when the warrenty goes out, they say you can bore and stroke it out to a 336 which I think comes out to a 5.4 or so. The shop that I spoke with said I would see about a 60hp increase with the heads and cams. Comp cams claims you will get more hp with the spings and phaser mods, Personally I would do them since you will be in their anyways with the cams, but that will also increase labor costs. I believe Brenspeed sells a n/a cam with good #s without changing the springs or phasermods if you decide to go that route. Livernois and FRPP sell some nice sets of cnc heads if you havent looked at them yet.

Porting stock heads isn't worth it, too much down time. You can get already CNC'ed heads from Ford Racing or Livernois. A custom grind set of cams specific to your application with the porting will net a nice amount of power. I was going to go the same route but your going to spend 75% of a supercharger and only 60% of the power gains.