You have 2 problems.
1. Edelbrocks DO evaporate empty after a couple of days. (Holleys don't)
2. You have a mechanical pump so it takes some cranking to get fuel back in the Edelbrock.
The insulator barely helps the problem on an Edelbrock.
(I have one as well and it barely made a difference.)
A full 3/8 circulating return fuel system didn't help either. (in hopes of cooler fuel at the carb)
People keep thinking fuel drains back, but it's not physically possible for the fuel to get sucked back out of the bowls.
That's what it would take for drainback to empty the carb and the engine not start. (can't happen)
I know what I'm telling you is true and fact, as I have been through it all myself.
Putting an electric pump on the car will fix the Edelbrock being empty at startup if you really want to keep it on there.
Running a Holley would make it so you don't need the electric pump.
I did run the Edelbrock for years with the electric pump and that worked well because turning on the key fills the fuel bowls back up before starting.
