Replacing the fuel pump on my 72 455...the pump that is on it has 2 inlets but one of them is blocked off. My 72 service manual shows a pump with a single inlet for all except the W30 and Toro. What is that 2nd inlet for? My first thought was emissions but doesn't make sense that only the W30 would have it.

 

Scott 442,
I believe the 1/4" nipple is for a vapor return line.

 

common for these cars with AC to have a third port used a a return line. non AC cars have only two.

 

thats correct. unless the non a/c car is a W-30, then it would have the vapor return line and 3 ports on the fuel pump

 

Interesting...mine is an AC car but the 455 isn't original...originally a 350 car but sounds like it should still have the return line. Maybe it's also plugged at the tank? Maybe I'll just buy a pump without the return line since it's not hooked up anyway and didn't seem to cause any probs...thanks!

 

First, the listing you are looking at is wrong. The additional port is the fuel return line, used on ALL A/C cars as well as all high-perf cars. The whole point of fuel return is to cycle hot underhood fuel back to the tank to cool off, thereby preventing vapor lock. If your car currently has the return line to the tank, it's not a bad idea to use it. If not, you can cap the third port on the pump with no ill effects.