Fuel System
 

Hello everyone, New Guy here.
I am also new to the Pontiac world. I purchased a 68 GTO about a year ago. The car had been sitting since 1999. The owner I purchased it from had never gotten around to getting the car road worthy. The engine wiring harness had been melted from what appeared to be grounding problem. My brother and I replaced the engine wiring harness with one from M&H. I ordered the harness for an electronic distributor and an internally regulated alternator. I changed all the fluids in the car and put some oil in each cylinder and rotated the engine by hand for about 15 full rotations. I disconnected the fuel pump from the tank and the fuel line from the carb. We sprayed some break cleaner in the fuel line from the carb to the fuel pump and let it sit over night. Next day we spun it over and got all the bad fuel and varnish out of the fuel pump. We then connected the fuel pump to a 5 gallon gas can with new gas. I spun the car over a to make sure the new fuel was coming out. I hooked up a clear inline fuel filter and plugged it into the new carb. She fired right up.

I say all that to ask this question. The fuel pump had 1 inlet and 1 outlet. However, the gas tank has a fuel return line. I check with the parts store and sure enough they listed 2 fuel pumps. One for an AC car and one for a non AC car (mine has AC). Can anyone tell me why the AC car has a return line and also would there be any problems not using the return line. The reason I ask is, it seems most new gas tanks don't come with filler necks, especially the ones with return lines.
Any help would be greatly appreciated .

Dean

Hi Dean. I hope you still have your GTO and are enjoying it! The fuel return line is usually there to cycle cooler fuel from the tank back up to the pump, hotter underhood temperatures with A/C make this more important.