Fox Mustang Magazine Issue 1 | Page 33

you don’t gain that much on a mostly stock engine. To make big power out of that car, you will need to upgrade the heads, cam, and intake, or add a supercharger. But even with that, it still won’t equal a brand-new Mustang. UNDERDRIVE PULLEYS Underdrive pulleys are a decent bang-for-the-buck. We’ve seen 5-8 hp on the chassis dyno with them. Some worry that underdrive pulleys will cause overheating or charging issues, but we’ve not found that to be the case. Unless it’s a 105-degree day and you’re stuck in traffic, or you have a large stereo system, we’ve never had any issues. Most often an overheating problem is due to a clogged radiator or worn-out clutch fan, not a larger waterpump pulley. The March pulley kit is the one we use the most. EXHAUST Commonly, people over-size their exhaust systems. They use a 3.0-inch exhaust on cars that really only need a 2.5-inch. Unless your 5.0 has big heads and cam or forced induction, it won’t make any more power running a 3.0inch exhaust. The bottlenecks on a stock 5.0 exhaust are the factory manifolds and cats. On a stock car, removing the cats is worth around 4-5 hp, but every car I’ve ever owned, except for all-out road race cars, has had catalytic converters. BRINGING UP THE REAR The other big bang-for-the-buck part is to put a numerically higher gear in the car. Most Fox Mustangs came with a 2.73:1 rearend for highway cruising. If you got lucky and someone checked the option box, it could have a Z-code gear — a 3.08:1. We recommend a minimum of 3.55 to as much as a 4.10:1, if you’re really looking for fast acceleration without too much highway driving in mind. WHAT DOES A GOOD 5.0 MAKE AT THE REAR WHEELS? A good-running 5.0 car will make between 195 and 200 hp at the rear tires. We saw less horsepower variance between 5.0 cars in their day than we’ve seen in the modular motors. They were much more consistent. ARE THE DERATED 205HP 5.0S REALLY WEAKER? The ’92 and ’93s that they derated to 205 hp — we’ve never seen any horsepower decrease in those motors. They make just as much power as the earlier cars. T-5 TRANSMISSION MODS People give the T-5 a hard time. I’ve owned hundreds of cars, including several supercharged versions, and the only T-5 I had a problem with was one in a road-race car where someone had run the fluid low and it overheated. But I don’t powershift any of my transmissions. That’s asking for trouble. FOX 5.0 VS. NEW COYOTE 5.0 It’s amazing how slow the Fox Musta