Originally Posted by NW 150

Bear and a few others on here will tell you that you need to know the total mechanical advance, as in the number where it stops rising as the rpms go up. You want it to be between 34-38degrees if i remember right. This is checked with the vacuum advance disconnected.

If I were you i'd use the 13L slot, and set the initial to 10btdc, and check what your total is after that to make sure what it is.