What psi do I need for my twin 40s

[69 panel porn]

I'm just fault finding on my bus and it's pointing to a new fuel pump I've got a facet fuel pump on it at the min and wanting to swap it for another,, but I don't no what psi it is and I'm strugglin to find out which 1 I need there is loads of different 1s, there is a 2 to 3.5 psi 3 to 4.5 psi 4 to 5 psi 1 and a 4.5 to 7 psi and I'm just con fussed now :?:
I don't have a regulator on it at the min so min couldn't of been that high psi I think any help please :shock:
Been reading logs on google and things like that and they say 3.5 psi but not sure please help

 

[K@rlos]

I had twin 40 IDF's on a 1600 with a stock pump and I ran them at 2.5psi. That's what eurocarb suggested.

Karl

 

[meowdmucker]

I fitted a CB rotary fuel pump when I fitted my 2110 with twin 44 webbers. This supplies a constant 3.5psi so no regulator is needed.