Timing

Forget stock. You need to measure the balancer and make some (at least temporary) marks so you know where say, each 5* is up through 40. Now set it "somewhere" so you know where it is, then rev it up with vacuum disconnected and find out how far it advances. While you are at this you might want to take a good hard look at the mechanical advance, is it rusty, sticky, or free? Shaft play? Are the points (dwell) set correctly and are the points in good shape.

Then when you figure out how far it advances, start with about 35 total and see where the initial comes back to.

Does this "have a cam?" Anything with any kind of performance cam, even mild, wants perhaps 10 BTC minimum, depending on the curve