99 04 Mustang GT Cam Swap Package

Alternative Auto has developed an impressive naturally aspirated package for the 1999 – 2004 4.6L Mustang GTs with P.I. heads that features a camshaft change and several other bolt-ons. We found a pair of replacement cams for the 4.6 2-valve P.I. heads that offer impressive gains over 3500-4000 rpms and don’t lose any TQ or drivability below 2500 rpm. These cams do have a “rumpy” and very intimidating sound even when just idling.

The accompanying rear wheel dyno graph shows the difference on a 2-valve GT that already had under drive pulleys, replacement throttle body with inlet plenum, X-pipe with high flow cats and a 2.5” cat-back system along with an Alternative auto premium fuel custom tune.  All of these mods are very typical of most ‘99 and up GTs in terms of bolt-ons and tuning. By switching to BBK long tube headers (which are one of the best long tubes for the 4.6L’s) and the cams that we’ve selected, we found big gains in both rear wheel HP and TQ, especially from 4500 rpm and up. In some parts of the dyno curve if you look beyond the peaks, the cams and long tubes were worth over 50 RWHP because of the normal drop off that you get with stock cams in the very high revs. And as the graphs reveal, this package actually gained some TQ in the 2000-3000 rpm range rather then loose as most would normally do because of the cams being to big, and the tune not done correctly.

It’s important to also understand that the computer tune for this camshaft and other related items in this package is extensively modified from stock. Alternative Auto has spent an extensive amount of time to get this package to feature a stable and desirable idle with great throttle response off idle and all other conditions. Because of how much cylinder pressure can potentially be bled off with big cams at low speeds due to longer overlap periods leading to a potential loss in low speed TQ, we extensively modify the fuel and more importantly the entire spark map in order to minimize low speed TQ loss and even enhance it, which is evident with this package on the graphs.

Everything done to this 2-valve still leaves it open to future mods including supercharging. The only thing that would have to come off for a typical blower install are the under-drive pulleys.

This set up will make for a very impressive over all package, especially if the car is equipped with a 3.73 or 4.10 rear gear.

Please call the shop for pricing and installation.