Re: 1963 Inline 6 Lead Additive or no
87 octane with quality oil 50/1 is all you need.<br />may want to adjust timing a bit to allow for new<br />fuel. not sure, but I believe merc put out a<br />bulletin on it and they said 23 degrees???<br />hopefully someone else will chime in to confirm.<br />you can also use the red "search" button above.<br />there has been tons of discussions on octane and<br />correct timing.<br />good luck,<br />M.Y.