I'm new to the modular motors, so cut me some slack. Bought my HD a few weeks back and have been reading the forums for a couple of months. I have read that there were limited to no benefits from installing headers on our motors (in near stock form). The theory that seems most accepted is the exhaust port is so poor, stock, that improving the exhaust manifold can't remove the bottle neck. My question is, why doesn't head porting get more attention? It would be much lower on the "visual" inspection by the "warranty police" than a pulley. I'm not discounting the pulley idea, but if the head would flow better, wouldn't we get more hp with less boost? This would mean less pressure, less detonation, and less heat! The Mustang mod racers seem to make more of this than we do here.

So, shouldn't we give this more thought? It sure sounds easier with my experience than trying to remove a press on pulley possibly damaging expensive bearings.

Has anyone heard anymore on the near future of aftermarket heads for our motors? They have been threatening this since early spring. Hopefully, the sparkplug issue will be addressed.

 

Most peaple find changing the spark plugs a challenge let alone swapping cylinder heads. It does look a little intimidating under there. This reminds me of when I had a Buick GN, there was a lot of head gaskets that had to be replaced back then and I suspect there still are. Someone once said that he didn't think owning one of those cars would mean also owning an engine stand and a cherry picker .
The PI cylinder head is not an easy piece to port. Its not a cylinder head that you can attack with a dremel tool and a jegs porting kit and find "easy gains" on. I do a lot of head porting myself, but I know when it is time to step aside and let a pro take over. The guy who did my heads is John Haskell (Aire Reasearch Inc. 253-848-1628)

John did find a lot of flow in the exhaust port, they went from roughly 140cfm to over 180cfm @ .500 and 28" h2o. The intakes were not so easy. He didn't loose anything at the lower lifts but the gains didn't start coming on strong until around .350 lift. And then they really took off, but if you are running stock cams (like me) then that is a small window of improvment. Even after all the flow work was done, I still don't know how they are going to run on the engine (its not running yet). Luckily this is one of the only things I did to improve power this time and it should be easy to tell what the heads are worth.
Anyway hope this helps
Dale

 

Assuming you have the 02 HD. Head work can be of benefit as you increase the amount of flow going in. The bottle neck seems to be in the exhaust valves. MM&FF did a test some time back on ported Lightning heads. They spent big $$ on porting and netted exactly 0 h/p. The gains lately have come from increasing the valve size in conjunction with cleaning up the ports. Long tube headers have been the only exhaust mod proven to increase h/p. The stock exhaust system is not that bad. Many are running deep in the 12's with stock exhaust. My only exhaust mod to date is a MagnaFlow muffler. Many rumors about aftermarket heads. Nothing real yet.

 

MM&FF only did one thing....port the heads. They didn't port match them to the intake. They didn't change out the stock valves.

I had my heads ported and polished and should be looking for a lot of hp out of them. They are rated on the flow bench at 260cfm on the intake side and 212cfm on the exhaust side. My '01 intake is port match to the heads and the exhaust ports are port match to my 1 5/8" long tubes which are 1 1/2" I.D.
I am/will be running aftermarket cams with aftermarket valves.
The porting was able to get more extensive because of the new oversize valves and it included a 3 angle job.

I still do not have it back together yet. I am having to switch out my valve springs. The first set was a bad batch and there were problems of snapping them. I am still waiting on my blower too.

 

Hi JD
The oversize stainless valves only have one thing going for them and that is that they are oversize. They do not flow as well as the stock valves. We only used them in my heads because John was able to reshape them into something that was useable. The oversize stainless intake is nice cause it sits a lot lower in the combustion chamber and doesn't promote turbulence into the exhaust port. But again that is about all it has going for it.
Dale

 

Did your head porter work the combustion chambers? I'm wondering if he ground down those "nubs" in the stock chambers. Do you have any pictures?

Thanks in advance.

 

Bad as L,
Could you shoot me an e-mail. I have a few questions regarding the work you had done. Your e-mail and private message is disabled.

 

L Truck
Yeah he worked the chambers but only were they needed it.

The piece behind (?) the intake valve was shaved on the back side a little but he did not alter the width or height. Since the intake valve is about a 1mm larger, the edge of the valve sits closer to that "Nub" and cuts off air flow on that side of the valve even more. I'm not exactly sure what it is there for but it was not our intention to alter it. I have done things like that in the past and paid the price for it by having an engine that detonates like hell or something just as bad.

Most of the work centered around the valve seats themselves. The stock valves sit kinda down in a pocket and there is a fairly substantial lip around both valves. That lip was blended into the recut valve seats and became an extension of the valve seat. The chambers were also lightly polished.

Ford put a lot of thought into these heads, the only thing that hurts them is production machining. The exhaust valve sits quite a bit lower than the intake valve in stock form and when you blend the chamber properly the exhaust port really takes off.
Since the SS valves are a completly different shape than the stockers and are not as thick, they really increase the combustion chamber volume. With some mild grinding and rashaping the combustion chambers went from 45 to almost 50cc, I think most of that was in the valves.

What the goal was here was to not go for maximum flow and reshape and hog out the ports until they lost what the factory had intended them to be. This engine reminds me of a Buick turbo V6 in that it makes a huge amount of power for what it is. There's some magic goin on in there and I didn't want to screw it up. My ports don't make huge flow numbers BUT I am extremely happy with the results.
And last....Yes I have pictures and I have no idea how to get them on here, but I will check into it.
Dale

 

Thanks for the responses, please keep us up to date as your trucks come back to life. I agree, these are not heads that I would take a bit to myself. I believe that head porting, especially on the expensive racing heads, is better left to someone with a flow bench and a little more knowledge than me.

So it seems that this is an area that is beginning to be more explored, but the MM&FF article you mentioned is a little disalarming. I thought for sure these trucks would respond to more exhaust flow.

With only 500 miles on her so far, I will just sit back and watch and learn from you guys for a time.