PI headswap


I finished putting ported PI heads on my '98 4.6 over Thanksgiving weekend and I only wish I did this sooner!

I spent about 24 hours total tearing the engine apart and putting it back together. About 2 of those hours were spent cleaning the deck surface prior to putting the new heads on. It also took me a while to remove the exhaust manifolds from the heads b/c I didn't have a deep well 13mm socket.

Overall the swap went smoothly with no unexpected surprises. The only bonehead mistake I made was putting the water pump pulley on backwards and shredding my belt after it ran for a few minutes.

The exhaust ports were ported to remove the hump right before the valve guide. The intake ports were untouched. Most of the time was spent on the combustion chambers polishing them and enlarging them to 48ccs to try to get close to the stock compression ratio.

Results: Since the heads were brand new, I put about 100 easy miles on the engine before I started pushing things. After those 100 miles, I started getting more aggressive and the truck performs noticeably different now. The power comes on more quickly and I don't have to put my foot into the gas as much as I used to. WOT is much better as well with the engine continuing to pull hard right up to the next shift.

I also haven't had any detonation problems with 87 octane, so I must have done a good job with the combustion chambers.


Next Steps: I'm going to start driving like I used to see if the new heads have any impact on my MPG.

I am also going to try porting out a spare intake manifold to see if I can improve the airflow to take advantage of the new heads.


95% of the information I used to do this swap came from ModularDepot.com. They have some great headswap and cam timing articles as well as tons of posts about doing the headswap.

 

Nice.

I've been thinking about this also... Did you have to re-program your ECU? Did it bolt up to the original intake manifold?

 

Jordan not Mike - it doesn't look like I'll need to get a tune yet. The truck intake manifold is probably enough of a bottleneck that it can't outflow the heads. If I can effectively work on opening up the spare intake, then I might need a tune for maximizing WOT.

The PI intake for the mustang/crown vic applications is substantially different from the non-PI intakes. So when those owners bolt on a PI intake, they get more air in their engines and could probably benefit from a tune. As you can see in the below link, there ins't much difference in the PI and non-PI truck manifolds.

intake comparison

I already had the PI intake from an earlier project (see below link), so in my case it did bolt just fine.

PI intake on non-PI heads

 

Thanks for the info. I'm sorta trying to figure out my options for when my motor needs to be replaced.

I was hoping that I wasn't stuck with the non-PI heads, but a whole, newer PI motor won't bolt-up to my factory wiring harness, I'm told.

Looks like I can run a built pre-PI 1997 motor and just top it off with PI heads and intake.

Thanks again

 

Ted,

Thanks for the great post and pics.

 

is it possible to do this swap on a 98 f150 4.6 using PI heads and intake to avoid the misalignment of gaskets and would that most likely require a retune? cuz man i would love to have that even if my engine and tranny have 155K mi on them.

 

yogi613 - PI heads and a PI intake are currently on my '98.

A few months ago, I had the PI intake on the non-PI heads. That what those pix that are on cardomain.com are from.

 

This is exactly what i have been looking for!!

My truck has a blown head gasket that I need to replace. Being an engine guy i just cannot see spending the money to do it without trying to improve the performance of the truck in some way.

I have a 97 4.6 SC 4x4. If I am understanding correctly the PI heads and intake are a direct swap onto my motor, it that correct?

I see brand new PI heads for $400 apiece fully assembled. How much is an intake and where can I find one at?

Is there anything else I will need? I will most likely be adding some aftermarket headers at the same time. Any advice on what works and what does not?

I see that in the swap you bought a timing chain and guides, are they different for the pi heads? Just want to be sure i have everything I need before I do the swap.

Also the PI heads come with stock Mustang cams. I am wondering if you used your stock truck cams when you did the swap? I use my truck for work and pulling trailers so power at 5k rpm means nothing to me, i want power from 1-3k. I see cams for $600, but I doubt I would have the money to buy new heads, cams, intake, and headers at one time, not to mention gaskets head bolts and all the misc stuff.

Anyone tried aftermarket cams aimed at low end power?

 

Anyone? I could really use some knowledge that i know someone here has. I would really appreichate it.

I just found Patriot-performance.com and am thinking of hetting the heads from them. Still not sure what else I might need to get this done.