HV vs Std Oil Pump Info

This particular MP HV pump has the Melling number cast into it and looks exactly like this, including how the numbers are cast in......But they certainly could get them from more than one supplier.

https://www.enginekits.com/m72hv-melling-oil-pump.html

The spring rate difference we got from the measurements matches up right on the difference between MP and Melling that you listed: 72 is 20% higher than 60....which is the spring rate difference we found.