Alright, I feel you need this...since you welcome and I do happen to know, -

Those heads will only flow so much NA and it's very easy to max that out. 260 RWHP is totally maxed...But you're not even close since you're are all intake and no exhaust.

Focus on the heads though, once you realize what they can do NA most won't bother.

Tuning ? One of these trucks ? Ford didn't leave anything on the table until gen 11. Unless you want to tow something and screw with the shift points a bit, tuning is a waste.

It's just the facts of these trucks...they're excellent vehicles and can be supercharged successfully fairly easily.

 

I knew someone was going to mention PI Heads, TrickFlow heads or heads being the limiting factor... which is agreed, and if 260hp is what your years here on the forums and with these trucks has proven, I'll lend ya that. Likewise, my lady friend that knows these trucks well said 260-280hp was all I'd ever get out of a 4.6l n/a... some kind of savant, but in a good way. My HP figures are just an estimate on what's reported and what manufacturers claim. I'm told I have a PI (All Aluminum) intake on non PI heads, which was (as I'm told) a 99 only combination and split the HP rating difference of PI / Non-PI. I really didn't pay much for any of the mods I've put on the truck, everything was either open box, clearance, used or a free mod so I'm not upside down in mods or anything. I'll likely just put BBK 1-5/8 headers on and call it a day on mods to this truck. I've thought about building a forged internal engine to just do WOT at my leisure... not that the patrol cars without forged internals were ever hurt running WOT year after year after year. What good is power if it's not reliable? What good are mods on a Daily Driver if you cant pass smog and drive it? I've done about all I can justify on this truck, and have come about as close to peak HP and I'm going to without a Supercharger that's more than the Bluebook value of the truck. It was down to $2500 KBB before the pandemic, but now I cant find a clean 10th gen under $7-8k here in Cali... so, I'll get my $3-4k initial investment, and less than $1k in mods out of it when I land a higher paying job where I can get into something that's capable of more.

 

Someone mentioned PI ?

 

Since you brought up PI and are a little mixed up. Only the 99 5fours received PI heads in 99. You could combine that set up with the 97/98 5fours for more compression and most powerful NA gen 10 F150 motor using factory parts. The 5four went PI in 99.

The 4six. You could combine a later intake from 01 plus gen 10 PI 4six intake. The 4six went PI in 01.

So you see how one could get mixed up between the two lol.

 

 

Hey hey... If I need swearing, I am married...

So at your 280.HP w a 4.6, a 5.4 should make 330-ish from its 265, ignoring so many variables, like my '01 has PI.heads and 285k. A mild time and a turbo is MY ideal. Oh - wife just rented a grand Wagoneer for a couple days. 4 cyl, twin turbo. I commend their thinking.

PS. Thx. I made some space, before they said this site is unreachable.

 

I also Welcome info. Some quick math on my '01 - 5.4, and assuming 2" dia runners, (which is unlikely,) at 100% volumetric efficiency, (80% maybe,) I get airflow in a runner at 1.6 fps @ 5000 rpm. I have a set of aluminum runners from the donor replacement engine, but unsure I'll ever get to them, if anyone in THIS sub- forum.is interested.

But while we all can probably appreciate JP's logical mindset, vis a vi, investing in a 4.6 of the tenth gen...

I'd like, JB, a bit of exposure to what Ford put on the improvable tuning table in the 11th gen.

I had a 97(?) Cobra. Later GTs had a lot more oomph. I know factories plan this, but I'm curious, even if me affording a turbo is unlikely.

 

It's getting rough out here... had a guy try and get into the receptionists car at work this morning, while she was in it no less. Had to call SLPD for that. While they were there, they ushered out a homeless camp right outside my office window.



Then my friend down the street called me to tell me he had just caught a kid trying to get into his car. Little does the kid know, that car belongs to South Salt Lake PD, because he's a school cop.

 

Xfinity.... damn you. There's a station that plays Columbo all day on Xumo Play. I've watched 5 or 6 episodes tonight.

 

That strange meteor chunk must of fell some wheres near your place. Goofy shiii be happening..