GM used a standard volume, high pressure pump but they are now discontinued.
Melling started thinning the amount of iron used in the standard castings so their standard pumps will not be suitable for a SHP engine - the castings can crack with high loads, RPM or solid motor mounts. You could spring 3 times as much $$$ for the Melling high performance line, standard volume, high pressure pump OR you can just get a Melling oil pump rebuild kit that comes with all new internals and both the standard pressure spring and the high pressure spring then put that into a good old heavy used GM casting. I just did that. Blueprint the clearances and run it.
