I know this thread is a little old, but here goes nothing.....

How old was your fuel pump? I have the exact some problem as you and I bought my fuel pump brand new 3 months ago - Walbro 255 LPH.

 

Mine's still working fine. In fact, everything is still working like brand new.

 

fuel pump was not that old.....i found out in my case that the rubber gromet that goes around the pump to hold it in place gets disolved in the fuel....kinda weird....im thinking its the 10% ethanol they put in my fuel....so i made my own gromet with Goodyear fuel line

 

Is 12:1 the highest ratio where you'll get 12 parts to one lb or is ther another step up from there?

 

12:1 works fine....it seemed to be the fuel pump all along... check this out

http://www.vortechsuperchargers.com/.../fuel_fmu.html

 

There is a 14:1 FMU as well I believe, but 12:1 is plenty.