Recheck your pressure after replacing the pump. Check it at the carb. Much easier. I have found stock mechanical pumps put out 10-12# and that is way too much pressure for all carbs.
Actually this is a good example of a shortcut making the job harder. I've done the "slant six fuel line mod" where you run a hose from the pump to the filter, then another hose over the valve cover instead of the hard line going around the front of the engine (the mod is supposed to reduce fuel boiling in the carburetor when you park with the engine hot). With that mod, I have NPT/hose adapters at the pump and the carb. I originally was going to check pressure at the carb, but I didn't have a female NPT connector that I could use to connect my Harbor Freight vacuum/pressure gauge. I decided it was easier to undo the NPT fitting at the pump than to remove the hose from the carb fitting (those hoses are a pain to get off). And you know the rest of the story.