High Volume oil pump or High Pressure oil pump?

[BananaDan]

My engine (based on the invoice I have) has the Melling High Pressure oil pump.  I asked the shop I used to reassemble and run her for the first time HP vs. HV pump and they said HP is the way to go so I kept it.  That being said, I see the HV pump recommended a lot here and listed on a lot of engine specs people list on this site.  So...

What is the difference and which is better for which types of applications?   How do I know if I am good with the HP pump or if I should have the HV pump?

MELM63HV
http://chucker54.stores.yahoo.net/brbhemhigvol.html

MELM63HP
http://chucker54.stores.yahoo.net/brbhemhigpre.html

[68X426]

Great question.

[justcruisin]

High volume is a bigger pump, high pressure just has a beefier bypass spring. What you need really depends on your application/RPM but for a stock build a stock pump works.

[Chryco Psycho]

The HV pump is Ok for engines with larger internal clearances but really requires a larger oil pan or you can empty the pan at high rpm on a long pull .
For most street builds I would recommend you stay with the stock volume pump & stock 6 qt hemi pan  , the hp pump just adds the black spring increasing pressure

[Cooter]

With an increase in Volume, an increase in pressure will occur. Not much, but around 25 PSI usually depending on the clearances.

I like to get all the oil I can to the parts. Just my "thing", but I also run stock volume pumps on cars I don't run hard. interesting note: On all my cars with the HV pump, the Pass. side valve cover tends to leak...On all my cars with stock pump, it doesn't.

[BananaDan]

Interesting.  So with a street build like mine, with the high pressure pump and the 6qt. pan, I'm in good shape?  Should I entertain a windage tray?

[Chryco Psycho]

absolutly the windage tray helps control oil & keep it off the crank supposedly worth 15 hp