Can a stock fuel pump produce too much pressure?
The M6866 is an old Carter muscle pump. It's rated at 7.5 PSI. That Delphi, the only rating I could find on it is 8 PSI. I found that here:
https://www.oreillyauto.com/detail/...f0135/delphi-automotive-fuel-pump/dlp0/mf0010Keep in mind though, those rated PSI numbers are "supposed" to be rated at free flow. So when they are installed and pushing against the fuel system, the PSI is less. I've never liked the free flow rating method. It's not very accurate, because you don't know how much PSI is lost pushing against the fuel system.