Hi all,

Thought I'd create a new thread here on a subject that I'm very interested in now. I would like to customize my 06 GT engine as much as possible without going to a power adder. I am eager to see how much I can do with this great engine, and looking for suggestions.

I'm sure you are all familiar with the usual suggestions: cold air intake, custom tune, mufflers, x-pipe, headers. That pretty much sums it up for the bolt-on stuff, and I'm eager to do these things (just installed FlowMaster American Thunder mufflers and love the improvement!).

But I'm talking about more dramatic changes once these trivial mods are done. Like new heads and camshafts. I've heard Comp Cams has 3 new sets of cams for the 4.6 3V worth upwards of 30 hp. I'm eager to try that out, but I also wonder if a pair of new heads would fit on this engine?

FRPP has listed FR-500C heads that work on the 4.6 race engine, which is stroked to 5.0. The heads are advertised as 4.6 4V heads for the 05-07, and are worth +60 hp. Does anyone have any idea if these heads are compatible with a stock 4.6 3V engine? Or could that be an error in the catalog? The price is not bad at all, especially when you consider the cost of a supercharger, which I don't really want to do.

A bigger question is this: Are these heads from the 2000 Cobra R, or from the 2004 Mach1? I'd assume these are R heads, since they're being used on the FR500. $1500 plus the cams is very affordable, and with the other mods we're talking 400 hp without a power adder--and I would love that.