Once past these power-producers, '99-'04 customers are turning to the chassis. Short-throw shifters are an A-list item, and then it's on to lowering springs, premium shocks and struts, aftermarket brakes, and perhaps appearance items, such as body kits. Of the latter, Mach 1 chin spoilers are fast movers because they are only $75 and black, so painting is not an issue-although it is an oversize item for shipping. Hoodscoops from Ford are also super popular, as are the Mach 1 grille deletes and larger radiators, for some reason.
What People Are Not BuyingFor the old 5.0 hands out there, a few heretofore must-have bolt-ons from the pushrod days are not on the equivalent 4.6 list. Headers, either short- or long-tube, sell, but not in the land-rush quantities they did for 5.0s. The reasons are simple-the 4.6 engine's massive exterior dimensions don't leave much room for header creativity, and if not sexy looking, the stock cast-iron manifolds are probably no worse than the crimped tube festivals fitted to 5.0s. Thus, there isn't a huge power increase to be had by fitting short-tube headers, just a few ponies. Furthermore, the stock manifolds' attaching hardware and gaskets are top-notch, and accessing the manifolds is not anyone's idea of fun.
In short, for what you pay, the installation hassle, and the modest power improvement gained, 4.6 short-tube headers are a relatively poor return on investment. In the end, they do make some power, but they are something to consider toward the end of your parts program rather than the beginning.
Long-tube headers offer more performance, but the cost is higher, the installation is more involved, and then there is the added issue of no emission compliance. That last thought may not be a real concern in your area, but in many parts of the country, where state inspections are mandatory, it is a complete deal stopper.
While X-pipes are hot, hot, hot with the '99 crowd, H-pipes are yesterday's news with the New Edge cars. Vendors say they still sell well on 5.0s, but likely the mellow X-pipe sound is a big hit with the later cars, and not so much with the H-pipe's throb. Likewise, where the 5.0 market was sold on cheap rumble, the modular market buys sleek, sexy Bassani and MagnaFlow after-cat systems by the trainload.
Intake manifolds have so far not made prime time, which is a no-brainer as until recently there have been so few to buy, and the Bullitt or FRPP alternatives are surprisingly big-ticket items.
Aftermarket or even ported stock cylinder heads are not a 4.6 mainstay. Again, with the exception of updating '96-'98 GTs with the PI heads that come stock on the '99 and later cars, there haven't been any cylinder heads to buy. FRPP has offered its High-Performance Cylinder Head for the '96-'98 cars only, and while it's a great head, it is a great white on the wallet, too. It's also worth noting that the Two-Valve PI head seems a fair casting to begin with, so unlike the choked 5.0 units or the lackluster '96-'98 castings, there has been a reduced need to upgrade these expensive and involved-to-install heads anyway.
One surprising note was the lack of sales on mass air meters and fuel injectors. It seems the market has figured out the stock parts are good to 350 rwhp, and even with all the bolt-ons, you'll be approxi-mately 45 hp short of that, so there's no need until you've stepped up to cams or more likely a blower.
Camshafts are not really a bolt-on, but have proven popular enough on 5.0s (maybe too popular with those looking for just a few extra horses). On 4.6s, the cam change is an involved job-not really difficult, but somewhat tedious in its length-and similar to short headers, the return on investment on a bolt-on car has not been exemplary. Again, they pay-off better once all the usual bolt-on parts have been installed. At that point, they definitely make more power than, say, short-tube headers.