If you have to ask that, you don't know how to use a timing light. Spring tension determines when full mechanical advance occurs. If you arbitrarily measure timing at 2500 RPM and call it done, you are making a mistake. Stock springs usually don't allow full mechanical timing until 4600 RPM.
To do it without a dial back timing light you can basically watch the timing mark as you gain RMPs and see when it stops moving can’t you? I personally like mine all in at 2000-2200 with my setup.
Oh yeah were talking stock springs. Ive gone through springs weights slots in the shaft, slots in the rotor plate every which way and back on buick hei. Before I had a dial back timing lite. Adj ustable vac. Or grind tbe slot window on the can. Real easy to make it ping if you max everything. Easy safe route is to buy a mallory 9000 from TA and have them set it to your specs. If you could go back in time when they sold mallory.
Anson, hit your edit button, and take your response and retype it AFTER the [/QUOTE], and it will be outside the quote. At the same time, backspace your original response inside the QUOTES.