Well this is pulled from another forum...
Still say its not worth it at all for what that cost. I'm willing to bet he is $10k into that drivetrain plus the cost of the Roush=just buy a 2011+ Coyote for cheaper.
First off, that's not a 4.6. Completely invalidates a fair comparison right there. Second, since it's has a rotating assembly, and the 38cc heads, I suspect his compression is way up there, probably 12:1 or so. And thirdly, it's on E85 (race gas). I bet that a ported PI setup with the same supporting mods would be north of 360.
And I agree about the cost. That's my whole point. That for the money, unless you are a very dedicated racer looking for every single last horsepower in a N/A setup, they're not worth it.
So you guys are trying to tell me a set of stage 3 ported heads, which are damn near as much as a set of TFS, is better than buying TFS? How does that even make sense? The added RPM range when boost is added to the equation would make for some great gains in numbers would it not? Not to mention the deck height difference. I don't know, if the ported heads were cheaper than they are I would say yeah worth a shot. But being damn near as expensive as a TFS.....
What other supporting mods will you have on this build?
You say the "added RPM range" would make good gains. Well, yes, it would. But will the rest of your setup be able to turn that kind of rpm? It takes a pretty expensive rotating assembly to turn more than 7000 rpm, and if you're going to do it constantly, you're going to need an aftermarket ECU. If you have an auto tranny, you're going to need a built transmission if you're going above 6500. See where this is going?
Are you still on the stock bore? Because if so, all that extra flow and those larger valves aren't going to net you much, if anything. That's the problem with these high flowing heads: it doesn't matter how much the heads flow when the cylinder size is the limiting factor on how much air can get in.
If you're on a stock bore, or only very slightly oversized (<.020 over), and don't have all the supporting mods to turn >7000 rpm, then a set of ported PIs will almost certainly suit you better and cost you less money. You don't necessarily need the biggest ported PIs (i.e. "Stage 3"). A set of stage IIs from most any reputable porter (MHS, Fox Lake, etc.) will suit you just fine. The MHS stage 2 package is a very good deal considering the rest of the parts that come with it.
And as I mentioned earlier, don't be afraid to try porting your own. I promise it's not nearly as "difficult" as some would lead you to believe. I spent around $150 on a die grinder, carbide bits, and cartridge rolls; got the valve guides and springs for something like $250; and got them all installed and a valve job done for around $250. So I've got something like $650 total in my set. I don't know what kinds of gains I got out of it because I didn't get the flow tested, and I haven't been back on the dyno yet, but I can tell that there are significant gains above 3500 rpm, and I can't tell that I've lost any below that.
