I think the spec is 16:1. Always a controversial issue on the AOMCI board. Some would argue you can use 24:1 with modern TCW3. But, you can't go wrong with the original spec.
Fred; I always use the mixture called for in the 50's, either 1/2 or 3/4 pt oil to a gallon of gas, or as Qt to 4 gallons. I use current standard outboard oil, I even run this mixture in my 50's racing motors, to include a modified Wizard Super 10 & have been doing so for years with NO problems. After 150 times out with a 56 Champion Hot-Rod which turns 8000 rpm's there was very minimal wear on the rings with hone cross hatch marks still visable on the cylinder walls. Also of equal importance is cooling, make sure the water pump is operating at its maximum, the powerhead should be just nice & warm to the touch after a 1/2 hr run.
