Taget fra Gene berg hjemmeside:

Two models of Holleys are the only pumps I would use. Both of these are pushers and are to be mounted at the tank. Use the Holley "Red" pump with the "Red" regulator properly set for the correct pressure called out in the carburetion instructions for 12 second power street and strip cars. For faster street and all out race applications, a Holley "Blue" pump is the only one I have found to do the job.
Furthermore, the "Blue" regulator offered by "others" with this pump is designed to be used for higher pressure than the carburetion used on VW's can withstand. For that reason I use the "Red" regulator with both the red and blue pumps and now supply the red regulator with the blue pump we sell.

Så meget kan du nok ikke regulere ned uden returløb.
Når jeg har brugt den slags,har jeg haft en pumpe der passer i tryk til karb. og så bare "dæmpet" dens pulser med en trykregulator.

Har problem med min holley fuel regulator. Sædet vil ikke holde 100% tæt. Trykket stiger til 14 psi. Har nu prøvet 3 stk, med samme problem. Jeg bruger en blå holley pumpe, og den giver 14 psi. Og det er en lav tryks regulator 1-4 psi.
Kører ikke med retur ledning til tank.

Håber at der er nogle der kan hjælpe, måske samme problem ?

best regards Thomas kiel