Head Flow Numbers
 

A great resource when deciding on a set of heads.

Flow Comparison for Most Ford Heads

Thats some nice info:nice:

I stickied this so that people will not have to dig and search through the forum to find it. Very good info.

Thanks :nice:

Thanks for the sticky Tommy.


It is interesting to me that GT-40 'P' heads flow better than the GT-40 heads that came off my cobra even though they have smaller exhaust valves

:shrug: improved runner design maybe?

I had planned on swapping to AFR 185's for my n/a combination that I am trying to configure. After comparing them to my current 165's and the cam I am wanting to go with, I am thinking it may not yield much better results over keeping the 165's

Lee,
The 185's work very well on a 331-347 N/A combination.....

I know a guy running Victor Jr's on his 347 and he's running 6.5x's n/a. And they are cheaper than AFRs.

nice post :nice:

The discussion possibilities of cylinder head flow, port size, and power potential are endless and often pointless.

It's what works best with your combo ultimately.

Its only pointless when you don't have a cam picked out. If you know in your cam profiles that you considering in your combo, knowing head flow #'s can be valuable.

:agree: but on the other hand there are a lot of people that pick there cam based on the rest of their setup (i.e. custom cam), making decisions on your goals for power curve, fuel economy, rpm range, specific usage, ect ... would be the first things to decide on .. then you have a couple decisions to make about how to go about meeting those goals. Knowing the flow rates is good general info either way imo. "knowledge is power" :D

Here's a tidbit of info for you guys:

Roush engine shop tested a 427 with a set of AFR 225's. Then, due to some unforseeable circumstances, needed to swap in another set of heads...DART, which is nearby Roush's shop, got them into a set of CNC 225's. Power was up 26 hp and torque was up 13 ft. lbs (everything else the same). And this was with a head that flowed less by the numbers at each lift. :eek:

Cool!
 

That is sweet and to think! I was just about to ask what the difference was in the gt-40 cobra and the gt-40 explorer! I was wondering, what year models on the ford explorer have these heads on them? and Do the gt-40 p heads have good enough valve springs for an E303 cam?

any explorer with a V-8

IIRC, the first Explorer with the 5.0L (year?) had the actual GT40 heads like the '93 Cobra. Then the subsequent ones had the P's... :shrug:

Just wondering. Why did ford make these different type heads? I mean if the heads made for the cobras flows nearly the same as the xplorer heads, why not just stick with one set of heads for V8's. I'm looking at cost and production. I don't get how ford would design so mean different things that are too closely related? I'm also not an engineer or automotive designer!LOL:banana:

performance improvement I guess.

The 5.0 engine ended in the mustang in 95. 5.0 explorers didn't come out until 96 or 97

I read where it was a last minute design change in order to bring the emissions down in the 5.0L in the Explorer (at least until the 4.6L was available). They wanted to keep offering a V-8 model, but the only one they had at the time was the old and tired 5.0L, so rather than sinking anymore money into the design of the 302, they decided just to try and redesign the head... and ended up doing a good job of it.

On a side note, the other reason why a set of P heads help performance is becuase of the smaller combustion chamber.... 59cc vs. the Gt-40 65cc. ;)

Lee,

You would be suprised what we are doin in class racing with port volumes etc. It goes back to bigger isnt always better, its velocity, and speed that makes HP

Heads
 

No TFS highports