26 qts total, 1972 DD 6-71N Johnson and Towers 310hp
If you change your own:
Change the filter (canister/cartridge style, not spin on), then
Add 22 qts, should match low mark on stick,
Add 2 more (24 total), should be at the high stick mark,
Run the engine, which will fill the filter (2 qts),
Add final 2 qts for total 26 qts.
Those are the instructions on top of the valve cover. P.s., use only straight 40wgt oil, such as Texaco Ursa, DD Delvac 1240, or other oils notated here in many posts.