[Formulajones]

You have a carb that doesn't survive anything over 5 psi?

Every mechanical I've had and used will always lose psi as it gets hot, not gain psi. If you're having a psi gain problem with heat or after heat soak, it sounds more like a fuel heating issue somewhere causing it to build pressure. Likely not the pump but something elsewhere in the fuel delivery system.

All the airtechs, AC's and Carter's Ive used (which are all the same pump) all vary a little bit with their psi but I've never had one that was over 8psi and never had a carb that wouldn't work with what ever psi I wound up with. Some were lower psi but what I never wanted was psi dropping under load, that's a worse problem to have.

These days I don't buy the store bought pumps like the wannabe AC's or Carter's because they have become too unreliable. The last Carter's I bought, first one died a block from the house and the second one died 4 miles from the house. The third time Napa just said never mind and refunded my money LOL. I depleted their stock that day.
If I need a mechanical pump these days I use either RobbMC or I'll buy a Holley mechanical from summit or something similar. I'm more curious as to why your carb is so sensitive to pressures above 5 psi.

As an example I run a summit brand Holley style mechanical on the nomad. I believe it's the 90 gph version but doesn't require a regulator. On cold start it has 9psi and it runs perfectly fine. After driving a bit and things get warmed up it drops to 7 psi and stays there. I consider this perfectly normal and the car drives and functions as it should.