Dad passed away in 2020...I inherited his 1963 62 series convertible....it had been sitting since 1997...I put in new gas tank...new fuel filter...had a new head installed with hard valves (to run on unleaded fuel)..had the Rochester 4GC rebuilt....now when the outside temp gets above 85F..the car vapor-locks and no fuel seems to be getting to the carburetor...have to prime it like crazy to get it started...when its cool/cold outside I can drive it all day long with no problem....out of answers.....FUEL PUMP?????????????????
As I'm sure Tony will agree, the reason that the old wooden clothes pin trick worked is that it insulated the fuel line from radiated engine heat. It did not, and wood does not, work as a heat-sink.
That's why some aftermarket carb-to-manifold heat spacers are still made of wood...while others are phenolic (resin) or aluminum. But, old school me prefers wood.
Anything you can do to insulate the incoming fuel from heat is a good thing.
Sometimes it takes a bucket of "good things" to fit a vapor lock problem. Especially with today's crappy fuel.