Spicy_Mchaggiz

If you're asking me, I bought the intake and tuner directly from JLT as they are 30 minutes away.

gmoran1469

The 3v heads flow almost as well as the 4.6 4v heads. It's not terrible.

jz78817

"not terrible" isn't "good." there's a reason the 5.0 Coyote made 100 more horsepower over the outgoing 3V 4.6, and it was mostly due to the 4.6's ****ty heads.

Simon1

I think the new heads are 4 valve, the engine is higher compression, has 40 more CI and I'm not sure what other improvements have been been made . So there is more than the heads that make the car have more power. The heads are temendously better on the newer Mustangs, but it doesn't mean the older ones are ****ty.

They flowed so well for their size and design that the aftermarkets don't offer huge gains. It takes a combo of cams, LTs, aftermarket heads and a blower to really make the power gains most want. They were touted at the time as being phenomonal. ****ty isn't a word that was tossed around. They were compared to the 03/04 cobra heads as being equal to them with one less valve.

Even with all that being said, the newer heads are really good and designed as the 3 valves should have been, with 4 valves.

Dino Dino Bambino

The 3v heads are actually very good, were a vast improvement over the 2v PI heads, and flow nearly as well as the 4.6 4v heads. The Coyote 5.0 heads are in a different league though and it's those combined with the 21ci bigger displacement, 11.0:1 CR as opposed to 9.8:1, TiVCT on double overhead cams as opposed to simple VCT on single overhead cams, and four valves per cylinder instead of three that gave the Coyote 5.0 97hp/65lbft more than the outgoing 4.6 3v.
In a nutshell, the difference between the 4.6 3v and the Coyote 5.0 is that the former is a very good engine while the latter is a great one.

jz78817

the issue with the 3v heads is really the single-cam part. with a SOHC head like the 3v Modular design, you can cant the valves a little but they're going to be on a narrow angle. They went for a "straight shot" intake port design, but without being able to cant the valves at a wider angle, the exhaust port has a far more dramatic bend and doesn't flow nearly as well:



a DOHC setup lets you move the exhaust valve angle so that you can increase exhaust port flow.

but even then, with DOHC you can have a (relatively) poor head design; when the 5.0 Coyote was launched there was plenty of talk about how its heads were even better flowing than the ones on the blown 5.4 in the Ford GT.