Goto Autometers website
http://www.autometer.com/hp/index.html
but to save some time here ya go
Ford 3.8L and 4.6L MUSTANGS ('96 - '98 only)
Tach output is obtained from PCM (powertrain control module) which is a 104 wire connector, and is located behind the passenger side kick panel. Look for pin number 48, which is usually an orange wire with a white stripe.
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2000 GT Laser red-5speed,MAC Cold Air, MAC 2 1/2" Cat-Back, 3.27gears, Pro-5.0 shifter, Weld Draglite's 15x5 and 15x10, 275/50-15 DragT/A's, 165R15 front, BBK Underdrive pullies, BBK offroad X-pipe with Dynomax super converters
Best Quarter mile run to date: 13.350@101.79/1.844 60'(7-6-01)Best MPH 101.79(7-6-01)