I have my 502EFI motors out doing a few maintenance things. I want to replace the oil pumps. Can someone recommend a good oil pump for these motors. Does anyone think I should stick with Mercruiser oil pumps ? I've heard Mellings are very good oil pumps. Recommendations please.

I would use a stock melling pump. not hi volume.

Thanks much for the input Noise Pollution. Why not the high volume pump ?

Any suggestions where a good deal on the Mellings pumps is ?

Just not necessary on a stock motor. Guys like to see a lot of oil pressure. Mellinig does make high pressure pumps.
They are standard volume high pressure.

Jegs or Summit racing .

Pressure vs volume

Pressure is created by the resistance to flow. For example, the water flowing out of a garden hose has relative low pressure, but when you put your finger over the end of the hose, restricting that flow, the pressure within the hose increases and you see the result by increasing the distance the water travels as it leaves the hose. The resistance to oil flow Inside an engine is from the clearances of the bearing and lifter bore. Engines with increased clearances will require greater flow to maintain the same pressure. As the RPM of the engine increases more oil is required. The oil pump selected should be able to flow the volume of oil required to maintain the pressure desired. A relief spring within the pump relieves the pressure when it reaches the desired level. High pressure pumps have a higher pressure relief spring as also do most high volume pumps. The main disadvantage of using a pump with the ability to flow more than required by the engine resulting in this bypass opening is a very small loss of horsepower.


More reading
http://www.cantonracingproducts.com/...s/melling.html