From this post:
The heads,etc from a car are interchangeable with a truck/van, but using the car intake will make the truck/van a gutless pig. Dimensionally, all Modulars are the same. There are small quirky differences between Windsor and Romeo versions of the engines that'll drive you nuts trying to finish up a swap like your speaking of. Bolt sizes,timing cover differences,etc,etc.
The 60rwhp number is bogus
By swapping the heads,cams,etc all out from that of a E150 or F150 with PI heads will get you 20-25rwhp. You've gotta remember,many of the people discussing the PI swap are talking about doing it on Mustangs that have a MUCH better flowing intake manifold,and they're usually swapping on a set of ported heads with aftermarket camshafts.
'98 NPI truck engines were rated 220hp,and the '01-up PI head truck engines are rated 240hp.
The cylinder heads themselves are honestly equals when it comes to capability of airflow-the camshafts, intake manifold, and the PCM tune are where all of the power gains come from.
There a minimal amount of power to be gained in a truck PI intake - it's still got the same restrictive design for low-end torque production as it's NPI counterpart-just ever so slightly less, and it's port shape is for the more squarish PI intake ports so it'll seal to the cylinder head properly.
As for parts sourcing based on years:
'97-'99 are the same
'00-present are all the same
This is based on the cylinder head type and camshaft specs. There are little differences through the years,but as far as power potential-the above is true.
I've driven both PI head and NPI head trucks- the '01 F150 work truck with PI heads (supercab 4.6L/4R70W 2WD) compared to my old '98 F150 with NPI heads and PI cams (supercab 4.6L/4R70W 2WD),and it was almost impossible to tell the difference between the two.
I would'nt touch the heads-I'd swap the cams and be done. There's not enough power gain benefit to offset the absurd amount of work to pull the heads,etc and the costs involved with head gaskets and head bolts,etc.