Al, for the record, I don't believe for a second that the extra capacity in the filter and lines does a thing at the oil pickup. All that matters is oil at the bottom available to the pickup/suction tube. I'm just of the opinion that the extended sump gives you more at the pickup tube AND lets you run the dipstick lower, helping with blow-by/vapors and pushing out oil all over. I made a huge breather can, with a drain back into the case. It worked very well below 4000, and worked above that with a crankcase evacuation system I fabricated, complete with a solenoid-activated valve set above 5000 rpm. The vapors were sucked out the exhaust, and it definitely kept the oil off the engine. But it did also increase oil consumption slightly, about a half-quart every 1000 miles.
With my old system and thin-line sump, I never ran out of oil or even saw a flicker from the oil light once, shifting at 6500 rpm OFTEN. Yes, I had a mechanical gauge on it for a while to see how it was under extreme driving conditions. I had a 26mm or 30mm pump(can't remember) with a Berg iron pressure-relief cover, plus a remote filter, thermostat, and fan/cooler. Of course my case is full-flowed.
I know one guy on here who had a flickering oil light often on corners with the vaunted type4 and it's supposedly superior stock oil system. Currently rebuilding that one due to LARGE crankshaft endplay due to lack of oil. As Gordon says, pffffft!
Eventually, I did as Stan did and went dry sump. I did this to alleviate an ever-increasing blow-by. It didn't work, the rings and cylinders were worn out. I rebuilt the top end this summer, and am back to new-engine blow-by, meaning little to none. I removed the sump extension as it is no longer needed. I have a two-stage Autocraft pump, a bolt on scavenge pickup, and a Jaycee oil pressure relief filter mount. Other than the standard filter, thermostat, and cooler it's really only a bunch of lines and the Speedway Motors 8 quart tank. I run about 6.5 to 7 quarts in the system, the tank is a bit over half full at idle. Yes, we check the oil engine running..... My system is not quite as complicated as Stan but it sure gives me a feeling of security when I hit the brakes at 110 into turn 1 at Lime Rock Park.