[Spridgets] Fuel Starvation

[Bruce Hamper]

I'm looking for some advice before I tear into the fuel line/pump of my
Bugeye Sprite.  I finished rebuilding a 59 Bugeye last fall and have been
driving the hell out of it ever since!  It has a 948 engine with original
pieces (carbs, dist, fuel pump).  The only upgrades were a Datsun 5-speed
(thanks, Gerard!) and disc brakes.  Now before you all plummet me with "Why
the mechanical fuel pump?", let me just say I was keeping it original.  It
has about 2000 miles since the rebuild and has been running fine,
except......
Last week after a 60 min drive in traffic and 90 degree heat, I parked to
go shopping.  20 minutes later I started the car, pulled out of the parking
lot and the Bugeye died in traffic.  My son did a really nice job of
jumping out and pushing to the first driveway!  A quick check found the gas
tank about 1/3 full, but no delivery to the carbs.  I'm guessing that the
mechanical fuel pump wasn't working and once the carb bowls were dry, the
car stalled. Just for your information, the fuel pump was new, Moss item in
2012.
We towed it home and after sitting in the garage a few hours it started
just fine.
Back in the day, did they all do this?  Is this vapor lock of the pump?
Should I expect this behavior from the mechanical fuel pump? Is the only
fix to install an electric pump?
Inquiring minds want to know,
Bruce in St. Louis