I have found some really good deals on PI heads and am thinking about picking up a set. I have a 98 with a 5.4 rated at 235hp. I have heard that the PI heads add 60hp but don't know how true this is. My motor has 130k miles on it so do you think I should freshen up the bottom end before bolting on low mileage heads?

-Chris

 

what does pi stand for? I figure they are from the newer 5.4 that produce more power, my block has 115,000 runs strong but I want to build up a motor on the side that I can swap in

 

power improved.

-Brian

 

I know alot of the Mustang crowd updates tyheir older 4.6 heads to the new improved PI heads. If you go to www.corral.net and do a search for "PI head swap", you should be able to find some pretty good resources.

As far as freshing up...what is the current condition of your engine? Does it burn oil? What kind of oil pressure does it hold?

 

HI!... cditch13 : 60H.P increase? NOT! If you install "99" - "03" P.I heads on your "98" 5.4 you will also need to get the matching "P.I" intake manifold, due to the intake ports having a different shape. The "99" - "03" got an increase from 235H.P to 260H.P and 330FT/LBS of TQ to 350FT/LBS of TQ with the addition of the "P.I" heads and intake manifold. But because you have a less dished piston on your "98" 5.4 you will have a higher compression ratio when installing "P.I" heads due to the smaller combustion chamber. Your current C/R is 9.0:1 and it will be raised to about 10 - 10.5:1 C/R with the addition of "P.I" heads. This will increase H.P gain a bit more. I would say you would end up with about a 35H.P (flywheel) gain, not much more than that. Remember though this is not a mod to do if you are planning on installing a SC at a later time, due to the raised compression ratio.

NON "P.I" and "P.I" heads. Notice the difference in the intake ports.

 

Thanks for all the info. My motor runs very well, no burning or leaking of oil so far. I was thinking of replacing the whole drivetrain if the motor or tranny broke on me, then I found these heads for a very cheap price and figured it might be cheaper to redo the bottom end and slap on these heads and have a nice fresh motor. I have also read that there are two trannys with the 5.4 and one holds up a lot better to increased power. How can I find out which one I have? Also, is there a downside to the raised compression ratio? Do the stock fuel maps still work? I'm not too sure if a Blower is going to go on this truck due to money constraints, but I would like to get a bit more power out of the motor. Sorry for all the questions, I have owned imports my whole life and this my first truck.

-Chris

 

Look on your door sticker and see if you have trans code "U" which is the 4R70W transmission. I believe the 4R70W handles less horsepower.

http://www.ford-trucks.com/articles/2003/9.php

http://www.fordf150.net/howto/decode.php

 

I have the "E" for the trans code.

So I have the E-4OD.
Also figured out I have a 3.55 non LS axle.

 

After reading many other posts here, I was under the impression that tranny code"E" was a 4R100.

 

You could be correct. Someone said the 4r100 was available on 1998 f150's.

http://66.179.14.118/forums/showthre...40d+4r100+door

 

Thats even better, considering I have heard and read that the 4r100 is a better transmission and handles more power.

-Chris

 

HI!... Just remember that the 4R-100 in your truck is not the same 4R-100 that's in the LIGHTNING. The LIGHTNING gets the strogest, top of the line 4R-100. Where the regular F-15's get the plain 4R-100. It's a bit stronger than the 4R70-W, but like twice the weight.

 

So what about the higher compression you get with these heads on a pre-99 motor? Are the stock fuel maps sufficient?

 

Anyone?