I ran the mopar stock 3/8 pickup 1970/71 440 6 pak pickup for the OEM 1970/71 Street Hemi 440 6 pak 6 quart oil pan in my 518 C.I. low deck stroker motor. I had to keep the oil level at or above the add mark to race it in a 1/4 mile, if I let it get down a quart the oil pressure would drop some after I let off in the 1/4 mile If was less than a 1/2 quart down it was fine I shifted that motor at or above 7000 RPM in 1st and 2nd gear and crossed the finish line at or above 6500 RPM the 10.5x31x15W M/T slicks, it would cross the finish line at or above 7000 RPM with the 315x60x4 ET Street Radials
I ran real loose oil clearances(.0035+ on the rods and .004+ on the mains, I used the narrow full groove Federal Mogul truck main bearings(4094M) also I oiled the rockers full time by grooving the #4 cam journal to make sure the valve springs got plenty of oil to keep them cool due to the solid roller cam spring pressures, above 680 lbs opened and 300+ on the seats That motor saw a lot of slow street driving and a lot of laps at the local tracks, 1/8 mile and 1/4 miles. My main message is the that oiling system served me fine I've used Milidon external oiling system before and since then also but there not needed for the application your building in my opinion