The short answer is yes, you probably can. Unless the engine is a turbocharged V8, you'll want to use the silver restrictors. (If it's a turbo V8, you can likely use the brass restrictors.) With the can upright and in a safe place, the yellow tubes under the air boots, and the vehicle idling, slowly depress the actuator of just one can until it locks in place. The idle speed should drop briefly and come right back up. Then slowly depress the actuator of the second can and, if the engine continues to idle well, lock that button in place. From that point you can follow the standard directions.