When you go looking to make serious power from your modular Ford engine, there's no better or easier route than forced induction. If you're looking to produce somewhere between 300 hp and 400 hp (flywheel), a normally aspirated 4.6L might be the way to go, but if you want to exceed that number, things start to get a little tougher.
The fact is, the 4.6 sports just 281 ci, and if you want serious N/A power, you'll have to add lots of compression and rev it to the moon. While it can be done, this generally isn't the ticket for a load of fun in a 3,500-pound street Mustang, unless you dig having 4.88 gears out back.
We know what you're thinking-we've exceeded that number by a fairly wide margin in previous testing, but there's a big difference between a supercharged motor producing even 400 hp and a normally aspirated combination running the same power level. In almost all cases, the supercharger (or turbocharged) combination will produce significantly more torque than its normally aspirated counterpart, this despite similar peak power numbers. Case in point, our 400hp supercharged combination pumped out a solid 35 extra foot-pounds compared to a comparable 400hp N/A combination. Things get even more one-sided when the power levels start climbing. That's because with forced induction the engine can swallow far more air and burn more fuel through the lower rev range.
We weren't trying to demonstrate absolute numbers but rather different recipes for reaching a desired goal. Was there more power to be had from these combinations? You bet, as with almost all forced-induction applications, additional power was only more boost away, but so too was it available by altering the specific combination.
Starting with the 400hp mark, we supplied recipes for producing 400 hp, 500 hp, 600 hp, and even 700 hp from your 4.6L motor. Used in whole or part, these force-fed foursomes should help steer you in the right direction.