91 octane to stop vapor lock?

No heat isolator. Front mounted. View attachment 1714814264

Was that your fuel line routing before you added the electric pump?

In that picture your fuel line is resting directly on the heater hoses. And its laying on the valve cover and then routed all the way over to the intake manifold.

That's not right. And a potential safety hazard.

Most vapor lock situations can be solved without an electric pump. Just need a well though out fuel routing with heat isolators and other things to block the heat (shields, heat sleeves)