[aerotest]

Yes spot on ....thank you for clarifying.

Originally Posted by 68 P.O.S.

^^^ That's great advice by aerotest there. Adjust the total timing to 36 degrees and let the initial sit where it's at. You want the springs that allow the engine to fully advance to 36 degrees between 2500-3000 rpm. Basically your cruise rpm. You'll have to test different combos of springs and recheck total timing after each change until you find the combo that gets you as close as possible. For the vacuum advance, aerotest is talking about manifold vacuum. You're vacuum advance hose must be connected to the port on the carb that has manifold vacuum. Manifold vacuum is the port on the carb that has suction at idle. Next, leave the vac advance set to 16 degrees. The magic number for your cruise timing is 52 degrees (total timing of 36 + vac adv of 16 = 52). After connecting to manifold vac, you're idle should jump up so you'll have lower it. You'll also have to adjust the carb to the new settings.