if i were to put on aftermarket heads, what else would i need to do? also what kind of performance gains am i looking at? And finally what is a good company for aftermarket heads? THanks in advance for any input!

 

there are no aftermarket heads. your stock heads are it. there are companies that modify these heads and sell performance packages, check out steenracing.com and VTengines.com for more info. power gains vary by application, but 280-300 rwhp with a head swap package and bolt ons is easily achieved.

 

Fox Lake Power Products

Click here^^^

THey have good stuff also for 4.6 heads.

 

By the way, if you call the guys at Fox Lake they are well vesedin your Mustang and can give you a very good idea of what setup will help you get exactly what you want out of your car. They were very helpful when I called a while ago to explore some options.

 

fox lake has been doing alot as well, they are a big player in modular performance. where do you live? if you live anywhere in the middle of the country, fox lake is probably the way to go.