I've heard of charging problems associated with many of those underdrive pulleys. I've also heard of sets that conpensate by actually making the alternator pulley smaller than stock to compensate for the other ones to cure the charging problems. You get (i've heard) 5 to 10 horsepower and many full sets cost like $90 or so (just guessing). They're fairly easy to install.
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'84 Mustang 5.0 T5, FMS aluminum radiator & 180* thermostat, 1 5/8 shortys/2.5" duals, '88 GT tail lights and wheels, Holley 4160 4 BBL, smog pump idler, now with hi-po collapsed lifters in #3 or #4
