how can i get more horse power out of my 1991 ford explorer

Easy ways to gain some horsepower include replacing the factory intake with a K&N cold air intake, replacing the cap and rotor with high-output aftermarket ones and heavier wires, and adding a higher-diameter exhaust. You may also want to add overdrive or underdrive pulleys to the engine to increase horsepower which makes it to the wheels instead of being wasted on the pulleys.