Here's how I Seafoamed my 1995 Nissan 240sx. I put 1/3 in the brake booster's vacuum line, 1/3 in the oil crank case, and the rest in the gas tank. It's recommended that you run your car for 100 miles with the Seafoam in the car's system, but I decided to skip this step. Be sure to do this in a well ventilated are because this stuff can stink pretty bad.
How, to, Seafoam, 1995, Nissan, 240sx, Silvia, S14, Zenki, Kouki, KA24DE, KA, KA24