If you want to swap heads on a 5.4 you should consider if you want to lift the cab or remove the engine.

Yes, the heads can be swapped with the engine and cab still in place but you risk damage to the heads or block mating surface. I have no way to lift the cab so I would pull the engine. Actually I have a 3" body lift so I can do it in the truck but for all others I pull the engine.

JMC

 

There is a dramatic difference between the NPI and PI intakes on a mustang. That accounts for the HP increase.


But as you can see in these pictures, with the exception of the intake port shape, there is essentially no difference between the NPI and PI truck intakes.

Truck intake comparison

 

ted, i think you have a good point, maybe that is why the 4.6 truck only went from 220 to 231 hp and the mustangs jumped about 30 hp. so that being said, is it worth the time and expense to swap heads to pick up 11 hp?

another thing to consider is that the mustang makes 260 hp as does the 5.4 truck engine, the heads and cams are the same so how come the 4.6 makes the same hp?

the article i read said that the non-pi intake was sloppy on the inside and did not tranision well.

i have seen flow numbers on the heads, would be cool to see flow numbers on the intake.

 

If you put the Pi heads on a non Pi motor you will not just pick up 11 Hp and 3 lb/ft of torque. You will also increase the CR to some where around 10 to 10.5:1. Ford dished the Pi piston to keep the CR down in the 9-9.5:1 range. If I were to do that swap I would look into a Stang intake and fab an adapter to be able to use my TB. The only thing that bothers me is the torque numbers on the stang. Max torque ( Pi head) of 293 on the truck is at 3250 rpm and the Mustang, 302, is at 4000 rpm. I am only guessing but I suspect that the 90% available below 2000 rpm of the truck is not the case for the car.
At lifts over .500 I was told that the non Pi heads out flow the Pi heads.
Sooo, I still have a set of bare Pi heads in the basement that I will swap for a set of cams that have over .500 lift. I talked with Mike and he found out for me that my set up can fit a .600 lift with no problems. All I need are springs.


JMC

 

Thanks for all the info! Would it be possible for us to use a complete mustang head, intake and throttle body or would there be too much fabbing involved to be worth it? I kinda wish someone made an after market intake that flowed better for us non PI truck guys that would bolt right up to everything without too much hassle.

 

What does PI non PI mean?

 

NPI means Non-power improved heads/intake

PI means Power improved.

I've learned alot about these swaps and other things on modulardepot.com. Great site.

 

I figured Commander wasn't around anymore, but I figured the bump to the top would generate some interest. Keep the info coming, I have a 98 4.6 in my F250LD and would be interested in this.

 

Dan7,

The basic difference between the Mustang engine and the truck engine is the placement of the TB. This effects
EGR location, the Throttle and cruise cables, the DPFE, the Cam covers. As I think about it I will surely find more things.

So if you are into fabbing brackets, hoses and pipes you should have no problem.

JMC

PS, drivability could be affectedd becasue of PCM tuning for cars and trucks is different.

 

Thanks for the reply JMC. Guess I would have to find a complete mustang upper end with the fuel rails and everything.

 

Not really, the PI heads have a better combustion chamber and just kill the NPI's on the exhaust side. Ported NPI can keep up with ported PI's on the intake side but that's only a part of the story.

Look at the engine dyno's, the PI headed setup made something like 25 more horsepower than engine with the ported NPI's.

 

just so i am looking at what you are looking at 5.0 mustang june 04, page 76

pi heads, intake and cams made 291 hp, 334 torque

ported non-pi heads, pi intake, cams 335 hp, 335 torque

ported pi headspi intake and cams 351 hp, 340 torque.

so i read that that the pi are good for 16 hp over non-pi. considering that from the factory the advantage is 25 hp. porting gains a little ground.

same mag.page 72

installing a pi intake with adapters to non-pi heads
made 30 hp more at 4600 rpm

the pi are no doubt better, just a matter of how much better for all the work involved.

 

HI!... Just so you know don't believe what you read about the 30H.P increase with the "P.I" intake to "NON P.I" head adapters. A friend of mine has a MUSTANG GT with the 4.6. It is a non "P.I" 4.6. He went to LIVINOIS MOTORSPORT and had them install a 4.6 "P.I" intake manifold and THEIR adapter plates onto his MUSTANG. He then had his car dynoed at their shop and they even supplied a chip and programmed it for him for the mods. He only picked up 7RWH.P!!!!!!!!!!! Let's just say he was NOT very happy and his car is not much faster than it was before. Mabey a tenth.

 

Neal did your friend put the "PI" heads also or just the manifold? Cause i thought you had to do the whole thing in order to see significant HP gains?

 

HI!... No, I'm just referring to a comment someone made about the use of a "P.I" intake manifold installed on a NON "P.I" 4.6 engine with the use of a set of adapter plates to make the transition from the "P.I" intake to the NON "P.I" heads. LIVINOIS MOTORSPORTS boasts a 30RWH.P gain with their set-up , but it doesn't happen. Plain and simple. My buddy spent over $2000 with these fools and got 7RWH.P. He's not impressed.