Definitely go with the aluminum. I switched from the plastic intake a few months ago and it feels like I gained some hp and tq. It is also louder under the hood, sounds great with the harley exhaust! I also ported my intake in a similar manner as Neal. I got the intake off my buddy's blown up motor, figured by the time he has the money to get another motor I can replace his..

 

I agree - Go Aluminum

 

Is the entire manifold aluminum? What about the bottom portion? Is that plastic I see? So far, all the information I have read is the entire manifold is Not aluminum.
What is the point then?
How much positive pressure can these manifolds withstand in a Supercharged or Turbo application?

 

HI!... The "99" 5.4 intake manifold is made out of aluminum, the TB is aluminum, the TB ELBOW is aluminum. The lower PLENUM is made of plastic (ABS).

LOWER PLENUM :

 

The 98 uses the same plenum, they also have a rubber jacket w/2 snapps that rapps around it. The entire manifold is aluminum.

 

Hey guys,

Thank you Neal for posting those pics. That confirmed what I suspected.
So is there an all metal intake manifold including a plenum?

What do you guys think about using one of those aftermarket manifolds for the 4.6L motor with spacers from Reihard Racing?

If it isn't practical then I will go with the 5.4 aluminum manifold with the, although regrettable plastic bottom plenum. I believe it would be better than the all plastic unit if you were to install a supercharger, especially a Kenne bell unit.

Thanks,
John

 

If your that worried about it - Procharge it then, but you'll have to wait for boost until the engine hits 2800-3000 rpm as happens with all centrifugal superchargers.

Other then that , look at how the Lightnings are engineered. Kenne bell, Allen (Mangnacharger) is the way to go to have all that above idle. I wouldn't be affraid of the plastic . You think the plenum will crack?

You could always turbocharge..

Go to "gotpressure.com" ..

 

nah, I'm not that worried about it. I will just go with the stock manifold. There is really no choice unless you build your own. Besides I don't plan on running any higher than 9 pounds of boost.
Thanks for the info.
Have pics for the porting and the modified plenum divider?

 

STOCK :



Divider removed and ports gasket matched :

 

There's also the coolant passage mod.



Gasket matched lower plenum :

 

i went ahead and made mine a single plane. helps out the top end.

 

Thanks for the photos,I have them all saved.
They will help me a great deal in modifying my manifold.

I just bought a Kenne bell kit from a friend that has the same year H-D F150 as mine. Its for the non-supercharged 5.4L motor. I think this is a better route than OEM Eaton swap from a Lightning or 02-03 H-D F150. What are you guys professional opinion on this?

Kenne Bell doesn't make this kit any more. I think it just didn't sell well, not because it was a bad kit.

John

 

I found a 97-98 non-PI aluminum intake manifold cast # F85E-9424-BE K046
Can this manifold be port matched to 99-03 PI cylinder heads or is totally different?
What are the differences betweenthe two?

 

that is non pi. You need the PI manifold, 99+

 

I hate to resurrect such an old thread but I need a question answered.

I'm considering purchasing an aluminum intake for my Excursion; the one I'm looking at has that coolant tube coming up from the intake on the passenger side of the manifold but my Excursion does not. Will I have any problems with this tube since my Excursion doesn't have it?