340 timing need some advice on rufff timing

What type of dizzy do you have. If it is a stock unit you are probably looking at 28 to 30 degrees built into it (mechanical). Do not guess with this. Agree with jefflock. You need a dial back light & some timing tape especially if you don't know specs on dizzy. You never want your total(initial plus mechanical) minus the vacumn advance to be much over 40 degrees & definately under 45.

Oldschoolcuda