Iron Horse - from what I have read on the Mustang sites, the intake side of the non-PI heads are pretty good. It is the exhaust side of those heads which are lousy compared to the PI heads (In addition to a better shaped port, the PI heads use a larger diameter valve). There is a rather narrow limit to how much you can open up the exhaust port on the Non-PI head because the water jacket is pretty close.

JMC - I think you asked about moving the powerband up by installing Mustang heads on an F-150. Again from what I've read on the Mustang sites, those guys claim that a 4.6/5.4 head is the same, regardless if it came from a truck, mustang or crown vic. They also state that the cams are the same.

That just doesn't make sense to me. It doesn't seem like the ECU could be the only thing that makes one engine product down-low torque, while making another engine produce high-end HP. I thought cams were a major player in how engines produced power.

 

Ted,

I believe that the Intake has something to do with it too. The longer the runner more low end torque that is produced or is it the other way around?

JMC

 

Are we having fun yet or what?????

 

If I had a '97 F150 with moderately high milage I would just spend a little more money and get a brand new crate motor with the PI heads for around $3,000.

 

JMC - you are right about the longer runners improving torque.

It was either on a T-Bird or Crown Vic site, but a person put PI cams on their non-PI heads and picked up around 15HP and 20 pounds of toruqe. Not too bad for a couple of hundred bucks. A lot easier than swapping heads.

I'm not sure what kinds of gains there would be on a truck engine, but I'm very close to finding out.

 

Go, Ted'98, Go!

Dumb question.......we would need to remove the heads to put PI cams in, right?

 

I knew I saved the link to the dyno for the camshaft swap somewhere:

http://mtcforum.zeroforum.com/zerothread?id=1363


The heads stay on to swap cams.

 

HI!... Your link does not work.

IRON HORSE : You do not have to remove the heads to changecams, but you DO have to remove the whole front timing chain cover assembly so you can remove the timing chains.

 

Thanks Neal! I was hoping it was like the "older style" engines.

Yeah, Ted'98, the link does not work.....but I may register at that site anyway and look for it.

I also spoke with a local performance shop. He said that if I try to do a "street-strip" polish job on my heads with the do-it-yourself-kit, WITHOUT a FLOWBENCH, I could easily do more HARM than good.

 

current Mustangs & fast fords Magazine has some descent info, chambers size , cam specs and flow numbers of modular engines.

 

I forgot that you have to register for that site.

It has some good info about modular engines, so it is worth the time registering for it anyway.

 

iron horse,
I think as long as the ports are all modified about the same amount your not going to make flow worse.
Does that mean they flow test heads thru-out the entire process. I think if I owned a porting business, I would give the same answer. I will post this from the standard abrasives web site:

There is a significant difference between basic head porting for a street-high-performance or weekend racer application and the very complex cylinder head work you see in a Pro Stock drag race motor or a NASCAR Winston Cup race engine. Doing full-on race heads requires the services of an experienced cylinder head professional, so Pro Stock, Winston Cup and similar heads are best left to experts. Basic head porting, however, is easy...so easy that even beginning hot rodders can do it well.

Basic cylinder head porting will improve the performance of any production cylinder head by removing flaws that come through mass production. Basic porting does not attempt to correct any design or engineering deficiencies. Once your porting project turns to that, you're beyond the scope of basic porting techniques.

My plan is to just open the heads to match the gaskets and round off all the internal edges and casting bumps, ridges or other marks. I will then polish the combustion chamber and exhaust port. If I stay with the stock heads, I will look into installing PI exhaust valves and perhaps a multy angle valve job just to make them flow a little better.
I already have Cams from a Mustang PI engine and I am trying to find out if they are the same as the truck. If so, I will sell my PI heads without the cams.

 

Here is a good link that covers the details related to swapping heads/cams for the 4.6

http://www.babcox.com/editorial/ar/eb40228.htm

 

Ted'98,
Very nice link, thanks. I can use that to identify my heads when I get home. It looks like the cams for all the PI heads are the same so they should be interchangable between the F150 and the Mustang.

 

ttt