[TomT/Williamsburg]

I have used conventional 20w-50 oil for quite a while now in my avatar, no oil filter of any kind, and I change it often. I add STP once in awhile too and I can remove my intake and show you a super clean lifter valley. An old Flathead racer once told me flatheads need heat to run efficiently, and run best between 2000-3000 rpm. I set my car up to run 2500 rpm @ 75 mph (running a 5-speed) and with temps from 170-180 degree temps no matter how hot it gets outside. I have also been across the country 3 times with many other trips in between and so far, no problems.