I have a return style system. These are the hellcat pumps. I talked to Walbro and the only difference between these and the 465's is the 470s flow 20% more. I figured out the issue. I deleted my stock FRPS and need to hook that back up so I can adjust the tune.
The only thing I did was change out from the F90000274 pumps to the F90000285. I disconnected one pump to see if it would idle and it almost dies. Plus my car is tuned without reading fuel pressure. It was bypassed because I don't have the stock FRPS. I use my AEM guage to read fuel pressure...
Im going to be between 900 to 1000hp. So I changed my fuel hat that had the 450hp because it was leaking at the top. Got a new Fore Hat with the 470s, kept base pressure the same, 40psi and my AFRs are 17 to 18 at Idle. Turned it up to 50psi and it drops down to 14 but then back up again to 17.