Vapor lock or a bad fuel pump? Any thoughts?

I HAD A PROBLEM SOME WHAT A WHILE BACK, i HAVE ONE OF THE SNORKEL CAMERAS, MY PICK UP TUBE HAD PIN HOLES IN IT, CAP LOCKS MUST BE ON LOL

Don't know if I missed it but I don't think so(?),I agree on the air leak could be the issue,but...
I didn't see mention of it might be as simple as the bowl gasket(?). If not seated right air can be sucked in and since the bowl doesn't fill all the way like it should you wouldn't see gas leaking out.
I don't think it's the fault of the vendor,others who have gotten pumps from them had only praise for them. I'd call them and ask,I'll wager they'd have an answer,pump's are what they do.

I agree, scottso. Those pot metal pump housings warp. Don't want to seal the gasket against the bowl. Yes.

yup, that's probably it ^^^^^^^^^but careful tightening up that glass bowl! they WILL break! don't ask me how I know this,,,,,

I vote you're sucking air... I saw similar condition on fuel bowl on my marine engine. The pinhole in fuel line did not leak fuel out but could suck air in. I have noisy carter electric fuel pump on my v6 because the engine does not accept a manual fuel pump. I would much rather have a manual pump, more reliable IMO and no noise. Could be any connection in fuel line whether at pump or tank.. Good luck, you'll find it the last place you look

I agree with your feeling on a mechaincal pump. I once bought Fleetstar for $350 beccause they couldn't get it/keep it running. It had an electric pump bypassing the defective mechanical. I replaced the pump and the truck ran fine. No more problems. The best electricals (Like Tolkiem in tank units) are good and expensive. Cheap "universal" ones are more likely to leave you stranded then a mechanical. Had my share of cheap electricals at a bus company, went with high quality Holley or Carter "race" (motor driven) electricals when mechanical replacements were not avaiable.

1984: Fuel line restriction. There is no such thing as "sucking" . A pump should reduce pressure in the fuel line between the pump and the fuel tank. It is the atmospheric pressure, on the surface of the fuel in the tank that pushes the fuel toward the low pressure area made by the pump.
My neighbour gave me his one year old F150 because neither he or his favorite shop of dummies could get the fuel to stop "boiling". The F truck would run slowly and stumble on poor acceleration. His wife called me and when I arrived, She signed the registration over to me. We towed the F truck home on a rope, it was less then 100 meters. My biker buddy crawled under the F truck and came out with a VICE-GRIP that he had discovered on the flex fuel line. Very suddenly and without warning, the Ford started to run like new. Well, it did have only a few thousand kilometers on it. My best guess is the clamp on the fuel line was in retaliation for something. I sold the F truck, at work, in a few days.