Source: http://forced4.com/v6project1.html

Spark Plugs:

Side note: Some people are using plugs that are one or two steps colder from different applications. They lack the unthreaded portion of the plug that extends into the combustion chamber and I fear will not function properly under any condition for long periods of time. Plug depth is determined by cylinder head design and the use of a shorter or taller plug will move the gap out of the target A/F mixture path. This is bound to have a negative effect on the combustion process, contributing to fouling, incomplete mixture burn and poor performance. If you run a non-standard plug like this just to get 1 or 2 steps colder, do yourself a favor and check them often and change them ever 6K or two oil changes. They are bound to foul like nothing you've seen before. Trial and error on gapping for F/I applications will be necessary in order to find a gap that resists blowout but at the same time achieves as complete a fuel mixture burn as possible.

Our cars use platinum iridium plugs from the factory. These plugs have a wide gap and run hot by design, a cheap way of self-cleaning, in order to resist fouling. This allows Ford to claim longer service life between maintenance. Under boost this can lead to detonation, even if the gap is adjusted. The solution is a 1 step colder plug. Because an exact one step colder replacement does not exist, the next best solution is to change copper, whichis inherently colder. Copper plugs have been the choice of F/I applications for years, and as it happens they are available for out cars. Your local auto store can cross reference the ford part number and find you a copper based plug. Some to look at are the Motorcraft AGSF24C, NGK TR5-1 or the TR55-1, that latter having a slightly larger electrode.

Note! The TR6 NGK plug, designed for the 4.6 2 valve engine has been tested on the 4.0 and despite it's shorter reach is now listed on NGK's site as a suitable replacement plug for the 4.0 V6. The great thing about this is it is a true 1 step colder plug than stock.

ORIGINAL: 996r916sps

Thanks!

I will mention the colder plugs to Lidio at Alternative Auto. They already changed to one range colder, but may want to step even further with more boost. That was a good point, that was one thing I didn't think of.

I'm not sure about IAT's, at 8psi the IAT's are below 100 degrees. At 10.5psi IAT's reach almost 130 degrees. This will be another area to watch.

404rwhp is awesome! I read the posts, I think he was running 360-370rwhp without the heads and cams. I don't think I will pass the 400rwhp mark, it would take some really good IAT's to even think of raising timing at all.

We shall see, I will probably get my duals finished up next week. After that I can schedule the adding of more boost and re-tune at Alternative Auto.

Thanks again!

ORIGINAL: 996r916sps
Hey,First of all congrats to scrming, I witnessed his car on the dyno and he has more power coming when that stock muffler goes away. I would guess 330/340rwhp.
But, back to my post.
I am going to drop to the smallest pulley Vortech sells in the 6 rib configuration. I will be swapping the 2.62" pulley in the next few weeks. I am working on getting my exhaust work complete, before adding even more power. I have not heard of anyone going this route yet. This pulley should net somewhere in the 14-15psi range. With this amount of boost, tuning will be the key. I would never approach this type of modification without a tuning professional. I would guess my revised power output may be in the 370rwhp area. It all depends on detonation. If detonation can be held off, who knows maybe closer to 390rwhp.
This will be a big step for me because I never thought these motors would take this type of power. If I can get a cheap car to drive everyday, I may consider going 18psi and race fuel. In order to up the boost past 14-15psi, you must have a custom crankshaft/balancer pulley made. I may look into this custom pulley later in the year.
Good luck to all, and I will report back when the tune has been finished.
Thanks!
P.S. - Has anyone gone 14psi+ or a 2.62" pulley? Any information may made my project easier, I appreciate any knowledge you may have.
Thanks again!