Advice on which fuel pump I should buy
 

I have a 2005 GMC Sierra 1500 with a 500 hp LQ9. 44# injectors. My tuner said I should go with a 255 lph pump. I just spoke with Walbro and they have a drop in unit coming out but its a 4 week lead time. I need something now. Which pump should I buy? Is there a part number out there? What is everyone else running?

Im building a similar set up and will need a new fuel pump also . Like the OP said, any suggestions on pumps and part numbers ???

I have a used walbro GSS340 (it's a 255 lph) that I bought from another member here. Right after I bought it, I bought a supercharger so I am running a walbro 450 now. Let me know if you're interested in it and we can work something out on the price.

AEM 320 is the way to go. About the same price with 30% more capacity without overpowering your stock fuel system.

AEM 320, will definitely look into that one