First off, I think it really depends if you do alot of highway driving or not...and if you're really only concerned w/ local streets and at the strip. I'd go w/ 3.73's for a manual and the 4.10's for an auto. Also, you're not gonna be constantly spraying, so get the gears that would be best on a NA car.
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'90 5.0 LX - heads, intake, cam, fuel delivery, gears, full exhaust, pulleys, ignition, drag springs, front brake upgrade, a/c delete, K&N cone filter charger.......and much more!
1/4 mile: 12.29 @115
60': 1.78
my Stang