Just wanted to mention - I put a new timing set and water pump on my truck, and while I was in there I took a stab at advancing the cam timing.
Used a Ford Racing adjustable timing set from summit racing - crank gear has notches so that it can be installed 2,4,6,or 8 degrees advanced or retarded, plus straight up. Total of 9 notches on the crank gear.

Installed the set with 4 deg advanced lined up, buttoned everything together.

It's no supercharger, but I would certainly recommend this change to anyone with a 302, stickshift, and the roller cam (351 firing order). It tames the hot cam a bit and brings the torque curve down to a more usable rpm. Off-idle power is much, much improved (I have a ZF5 with 3.55 gears and 33" tires), engine note is a little deeper. The power gain is gone around 2000 rpm, from 2000 - 3500 it seems about the same, however the motor seems to run out of breath a bit earlier than before. Not that I often rev over 4k, so I don't mind it one bit.

If you have an automatic, you won't notice much with this change, because the engine is never below 2000 rpm when you have the pedal down.