Electrical Gauge Wiring Of 94 Carbed Mustang


Active Member
Dec 25, 2012
Hi guys,

I've been working on an engine for the last few years and finally got the engine dropped into place in the 94 Mustang I picked up. Originally the engine was going to go into a 79 Mustang Ghia but unfortunately that vehicle was stolen from me so a few things will be slightly different for my wiring from what I originally was counting on. Anyway, I am writing to find out if there is any special wiring I will need to perform to make sure my gauges are functional. The guy I bought the car from had installed a SpeedChanger system made by Terf Inc. and is an onboard way to adjust the speedometer function. It is unclear to me whether or not I need the onboard computer to ensure function of this device and my speedometer from the directions that are included. He mentioned that there is 3.73 gears in the rearend but I don't believe he ever changed the speedo gear because of the ability to compensate with the SpeedChanger. The link to the manual is here ( http://www.dragonaero.com/Data/SPEED%20CHANGER%20CALIBRATION%20MANUAL%20TERF%20102302.PDF ) . The previous owner had a supercharger in the car so there is an MSD 6 BTM ignition box currently installed.

I will be using an MSD ready to run distributor and coil. I don't think I'll have a problem with the tach signal or the other gauges (volts, oil pressure, water temp, or fuel) but I'm really not sure on the speedo.

If anyone has more experience with swapping a carbed engine into the 94/95 mustangs please leave any information you can.

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