Yes a bypass would work. Get one with a dual butterfly in it so it shuts off the primary exhaust and redirects all off the gas flow to the bypass. Next is operation - manual cable, electric solenoid or vacuum solenoid? What diameter exhaust do you currently have? Your current exhaust sounds raspy - a straight through will be hell noisy. I've thought about doing this too but was thinking of having the bypass body somewhere under the cab and have the exhaust exit the side of the truck.