milkenit

Hello all. I have a 70 cutlass that had a 1969 455 installed by the prior owner. The fuel pump appears to be bad and I’m looking to replace it. However, there’s a fuel return line not hooked which I assume was hooked up on the original 350 engine(that too is an assumption)So I guess my question is does or did the 69 fuel pump have a return line to the tank? Would it affect the performance if I bought a 3 port pump and hook that back up? Not sure if it matters but it does have A/C. Thanks in advance for the help.

Sugar Bear

AC is what matters. Either pump would work, personally I'd use the one for the car and hook up all the lines if the line/fitting to the carb lines up.

Good luck!!!

BackInTheGame

Check on the tank. If there are two lines/nipples on the tank, then you should get the pump with three ports. The larger of the two lines is fuel supply, the smaller is the drain-back/vapor line.

PatL

As others said the three port fuel pumps returned fuel to tank to reduce vapor lock. I believe, depending on the year etc, the cars with A/C used it.