Fuel hose is too small for this. It comes off a tee fitting on the oil bath air cleaner and goes down the firewall and right frame rail then crosses over to the left frame rail and then to the vent on the hydrovac. OD of the fittings is 3/4. I’ve seen later trucks use a little breather in the cab corner that the same hose goes to but mine connects to the top of the oil bath.