Cab, the carb is a 4779-5. Its got stock jets 70s/80s. I am in NE Ohio, think we are around 800-1000ft above sea level here. I cannot remember which plugs I have in the car. I'll look today.

Mattax, this is great info. Thank you. I'm not sure how much mechanical advance this distributor will give me? But, it sounds like I should open the slots the whole way (to give me full mechanical advance) and I'll bring my initial back to not overshoot all of the mechanical being added. At the moment I closed the slots down some to stop the mechanical advance at 20 degrees since my current initial is 18, for 38 total.

I'll have to see what springs I have. I don't recall having more than came with the distributor, but I'll look. If not, I'll pick up a spring kit.

650 RPM idle speed with a manual, or was that auto with auto trans?

Thanks again.