Wrong on the mpg and power, a properly working air system doesnt hurt anything, to actually get more power and mileage all the emission crap has to come off, which wont work on efi systems because it utilizes the emissions crap, the only real power\mileage boost is long headers and duals. If you want to measure the belt length, get a seamstress tape measure, wrap it around the way the belt goes less air pump, and take a 1\4" off for tension.
"Its a Ford. Nuff said. Everything else is just a glorified tonka toy"
"ASE" Certified" Parts Professional
92 F150 302 4x4 Long bed Extended cab
2001 Taurus wagon