If you do it right you can gain gas mileage,there will be a gain in horsepower and torque depending on the supercharger that you use one will be more then the other, and there is a factory supercharger that is on the thunderbird 91-95 that i do think bolts onto your motor, ford dont change much from year to year on the motor. and google paxton superchargers, you will need to upgrade fuel pumps and the best one besides the walboro 255i is the 89-92 ford e-150 fuel pump it is the same thing as the high performance fuel pump for half the price and a direct bolt on instead of modifying it.

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