Ok, so if your fuel pressure is 40psi with no vacuum signal, doesn't that mean that
its relatively 40psi always? What I mean is that if the same 40psi base is 50psi and 10psi boost, then the 10psi will be fighting the injector making the 40psi net. That is always how I've logicly put the 1:1 fuel pressure rate together in my head, but is that wrong?

What do you mean by fighting the injector? If you've got a 40psi base, at 10psi boost you've got 50psi fuel pressure where's the fighting the injector part come in? It should remain a steady 10psi above boost all the time if that is how you have it set. The fuel pressure should match boost for every 1psi it makes remaining that 10psi above boost pressure.

What I'm meaning is that if your pressure is 50psi at 10psi boost then your relative pressure is 50psi - 10psi = 40psi

You are correct. With a 1:1 regulator, you will always have the same pressure across the injector, regardless of manifold vacuum or boost pressure.

Marty

Yes that is correct