questions about oil pressure

Hi all. My '76 CJ5 with 304 has been showing low oil pressure on the little aftermarket gauge that was installed on it when I bought it.
When I first start it up and it's cold it will idle at about 800-900 RPM and read about 60 psi of oil pressure. As it warms up for 4-5 minutes the oil pressure drops to around 25 psi or so at idle of about 700 RPM. If I take it out on a short highway trip, then after about 5 miles of crusing at 3000 RPM, the oil pressure drops to about 20-21 PSI at that 3000 RPM engine speed. I got these readings today, just a few minutes ago right after installing an oil pump rebuild kit that consisted of 2 gears, a gasket, and a spring/piston for the oil pressure relief valve thingie. My engine temp never reads above 210 and it idles just fine even after highway cruising for several minutes, but when it idles after the highway trip the oil pressure is so low that the gauge doesn't give me an accurate reading, it's like it's hard to tell what the pressure is once it drops to arout 5 PSI or so. So all in all my Jeep starts right up, runs great, stays cool (no more than 210 degrees) idles fine, has plenty of power, doesn't blow any smoke out of the tailpipes, no backfiring, etc, etc, etc, but the oil pressure reads low. I'm not sure if I should be worrying or not. I doubt the gauge is bad since it reads 60 PSI when I first start up the Jeep and it's cold. It's one of the mechanical gauges that has a high pressure oil line running straight to a little screw-in fitting on the engine block next to the oil pump. Seems like if it reads ok when cool that it would read ok when hot. Can I get some input from y'all as to whether or not I should be worrying or what I should do next? Thanks for taking the time to read all of my ramblings.
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Here's some details about the oil pump rebuild I did this morning: http://jeepadventures.dyndns.org/jeep/oilpump/oilpump.html

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I was trying to save myself from snipped-for-privacy@4ax.com,
| Hi all. My '76 CJ5 with 304 has been showing low oil pressure | on the little aftermarket gauge that was installed on it when | I bought it. When I first start it up and it's cold it will | idle at about 800-900 RPM and read about 60 psi of oil | pressure. As it warms up for 4-5 minutes the oil pressure | drops to around 25 psi or so at idle of about 700 RPM. If I | take it out on a short highway trip, then after about 5 miles | of crusing at 3000 RPM, the oil pressure drops to about 20-21 | PSI at that 3000 RPM engine speed. I got these readings | today, just a few minutes ago right after installing an oil | pump rebuild kit that consisted of 2 gears, a gasket, and a | spring/piston for the oil pressure relief valve thingie. My | engine temp never reads above 210 and it idles just fine even | after highway cruising for several minutes, but when it idles | after the highway trip the oil pressure is so low that the | gauge doesn't give me an accurate reading, it's like it's hard | to tell what the pressure is once it drops to arout 5 PSI or | so. So all in all my Jeep starts right up, runs great, stays | cool (no more than 210 degrees) idles fine, has plenty of | power, doesn't blow any smoke out of the tailpipes, no | backfiring, etc, etc, etc, but the oil pressure reads low. | I'm not sure if I should be worrying or not. I doubt the gauge | is bad since it reads 60 PSI when I first start up the Jeep | and it's cold. It's one of the mechanical gauges that has a | high pressure oil line running straight to a little screw-in | fitting on the engine block next to the oil pump. Seems like | if it reads ok when cool that it would read ok when hot. Can | I get some input from y'all as to whether or not I should be | worrying or what I should do next? Thanks for taking the time | to read all of my ramblings.
Sounds like it is overfilled...the oil is foaming....I have the same problem when I accidentally put in an extra quart...draining some out helps me...
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