I'd like to know what upper/lower intake I should use with GT heads/cams if I perform the swap. Should I go with the Bullitt intake? Will it fit? Also, will the extra lift from the GT cams cause a problem on a non-PI engine (don't want a valve hitting the piston!)? I'd really like to perform this swap this summer, and I just need to know the particulars concerning the fine details (i.e. what gaskets to use: Mustang or F-150; will the same headers fit, etc.)

-Flea

 

Hi Flea,

Good to see you again!

This really isn't appropriate for discussion here as it's far too detailed to type it all out - you don't learn all the ins & outs of a cylinder head swap on mod motors on a message board.

I'll get you some quick brief info for now, & then you can call us for details.................

In general, with cams that maintain a 114 degree lobe centerline you generally don't have to worry about hitting the pistons when adding PI heads to non-PI motors and using the GT cams - you *will* see a resultant & significant compression ratio climb, to anywhere from about 10.2:1 to 10.6:1 - most commonly right about 10.3-10.5:1, so you'll *always* have to use the best premium gasoline, and you do need to be tuned accordingly.

The thing to remember about using the Mustang GT cams & valvesprings is that while yes, they *do* have more lift, you don't gain much power just by changing to higher-lift cams in the Ford Modular motors, either in PI or non-PI heads unless you *port* the cylinder heads. Their cams are well matched to the heads and their flow characteristics.

The Bullitt intake is OK, it certainly is an upgrade over the stock truck intake - but it's kinda pricey and may require other changes, too. Most just use the truck intake and port it, making sure to remove the boss inside where the hook comes down to move the intake assembly down the assembly line - machining out that boss alone is worth about 7-9 HP. Then port it by hand & Dremel (etc.) as best you can, port-matching to the gaskets - then send it off for Extrude-honing, & you'll have a nice manifold.

Good luck!

 

ok mike i am totally confused.
i got my new "5.0 mustang & superford" today. they have a great project involving droping a 2v 5.4 into a mustang (Talks about the intake thing) and it has dyno graph before and after tunning.) in latter issues they plan to dyno all the bolt ons and swap cams.

anyway the reason i am confussed is because the article say that all pi heads have the same cams, no matter if it is van truck or mustang. ( this might explain why the 4.6 is only down around 30 hp but torque is down 55lbs.) in the article, the 5.4 with custom adapters runs a mustang intake, even with the shorter runners the peak tq was at 2500 and peak hp happened at 4500(after tunning)

this is a great article for anyone considering the 4.6 to 5.4 engine swap, they picked up a 5.4 with 4000 miles for $1150. it is going to be the closet thing we truck guy have ever had for a how to and whats it worth.

 

Hi Brotherdave,

You know, I've never actually tried comparing the part #'s, nor do I consider myself a Ford camshaft "expert," but that doesn't sound right...................

The 5.4 F-150 got the PI heads in 1999, the Expedition in 2000, and the 4.6 F-150 got them in 2001 - but even among the PI heads, the trucks and the 4.6 Mustang GT's use different cams - the Mustang GT cams have significantly more lift (well over .500), and a profile that allows them to make power for another 1000 rpm or so *beyond* where the truck 4.6's fall way off - and the intake manifold alone didn't achieve that. On the dyno, the '99 & up Mustang 4.6 GT continues to make power after the truck PI 4.6 is already on the way down the power curve - and it's the cams that primarily control the basic power curve & operating rpm range of the motor.

It is true that these cams all generally stick with 114 degree lobe centers - so does virtually everyone in the aftermarket, even Dave Crower - that's to avoid valve to piston clearance issues at higher lifts (up to about .600 or so) in these interference motors, even when swapping PI heads onto a non-PI motor & the resultant CR increase.

The heads themselves are interchangeable on the 2V mod motors, that's mainly just a matter of using the right cam covers & cam gears.

Typically, among the shops doing race-prepped modular cylinder heads the '99 & up Mustang GT cams were the way to go - for a time it was the only practical cam upgrade available. Then the aftermarket started providing reground factory cams, which required the use of lash caps, etc. and then finally, over the past year or so, about 5-6 cam makers are now making good cams for these motors (non-regrinds, so that lash caps aren't needed, and reliability is maintained).

By the way, we have yet to see a 5.4 motor make it's peak torque at only 2500 rpm - it's usually more like 2900 rpm on a chassis dyno in our experience, and the 4.6's torque peak is even higher. Though it is true that for most years, Ford rates their 5.4 2V motor's torque peak at only 2500 rpm.

A few months ago, MM&FF did an article on a 5.4 swap into a late-model 4.6 Mustang. They also did a decent article on the modular cylinder heads over the past 4-6 months that is worth reading, in a 2 part series - first the 2v's, then the next month they did the 4v's. That is worth checking out if you can get the back issues.