SBC: How much oil pressure is enough?
'65 Nova, 350 V8. Has a standard Melling oil pump. To drop that engine in this vehicle we needed to use an oil pan that would fit around the center link. Engine has barely 100 miles on it.
My problem is this - recently installed a Summit brand oil pressure gauge, and it tells me that when I start it up cold, at idle I'm getting about 20 lbs, and around 40 lbs at 2,500rpm. When it's warmed up, I'm still getting 30-40 lbs at 2,500 rpm, but at idle (about 800 rpm), this gauge is telling me I'm at less than 5 lbs.
Prior to the gauge & sending unit, it had the stock sending unit & idiot light. When I turned the ignition switch on (not starting the engine), the oil light would come on as you'd expect, but was never on while the engine was running, so I'm inclined to believe the old sending unit was operational and pressure was sufficient. This gauge I installed is not a high-dollar gauge, and I really only installed it because I needed the water temp gauge that came with it (stock water temp sending unit was reporting 'hot' at about 120 degrees, opted for gauges rather than replacing stock sending unit - and btw the water temp gauge tells me I'm only getting up to about 155 degrees with a 180 degree thermostat, so I'm kind of wondering about the quality of these gauges - anyone have bad experience with Summit brand gauges?).
I know the best thing to do it to get another gauge & hook up to my oil pressure tubing (btw, have checked tubing, no kinks) & see what it says, and I intend to. Would like to hear from the cumulative expertise on this forum what you believe to be adequate oil pressure for a SBC. The car will not be raced, or even mildly abused. This one is for my wife. Is a mild build - streetable cam, 9.5:1 pistons, 650cfm Holley w/intake, nothing radical.