[storm9c1]

One way to eliminate fuel problems is to test the fuel pressure. Buy a diagnostic fuel pressure gauge and temporarily tee it into the fuel line right at the carb inlet. Run a rubber hose under the hood and through the window and keep an eye on it during a test drive. Of course use clamps on the hose and be smart about the routing. It only has to last a drive or two.

When I did this, I noticed my fuel pressure would drop to zero and a moment later the engine would die. Turned out that the PO put a filter before the pump and on hot days, the pump couldn't get enough volume to keep up with the carb (and easily vapor locked). I had to move the filter to the pressure side. And running multiple filters doesn't sound beneficial either.

If that checks out OK, then it could be ignition related.