I added 6 quarts oil to my new 261 with stock filter. I ran it to seat the cam shaft and let it sit.

I then filed a little notch on the dipstick of unknown origin at the oil line. I keep an eye on that notch but I use very, very little oil between my Spring and Fall changes. I haven't worried about an "Add Oil" mark.

1948 3/4-Ton 5-Window Flatbed Chevrolet

34 Years. Now with a '61 261, 848 head, Rochester Monojet carb, SM420 4-speed, 4.10 rear, dual reservoir MC, Bendix up front, 235/85R16 tires, 12-volt w/alternator, electric wipers and a modern radio in the glove box.