1. Yes, plug it. If the port remains open to atmosphere performance will be poor. 2. Yes. The single stage fuel pump was standard when your truck was new. The double stage was an option. Fuel pump outlet pressure is 3-1/2 to 4-1/2 psi. Higher pressures may cause your carburetor to leak or flood so check with the seller before purchasing.
Rebuilding a used fuel pump can be more than installing a new kit. GM (AC/Delco) stopped carrying the original appearance fuel pump more than 50 years ago. These pumps are well worn now. A common problem is wear at the rocker pivot pin. Wear into the housing may require a machine shop rebush. These pumps are best repaired by professionals unless you are fortunate to find a NOS one. Even NOS require a new Ethanol tolerant kit.
About 30 years ago AC/Delco made replacement fuel pumps to replace the old pumps. The replacement pumps have tops that are pressed on, not easily removed for repair (see picture). This style of pump is no longer made.
Today most of the new replacement pumps are made by a pool of various Asian companies. Quality Control is an American word that has a different meaning in Asia. The larger chain and on-line auto parts stores pay extra to get the better pickings of these pumps. Before you buy one check the warranty and keep your sales receipts in case you need a warranty return or refund.
Last edited by buoymaker; 12/18/20224:00 AM.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
