My 360 build

That above is what I was eluding to. Once you find out how much initial your engine takes without the starter kicking back when you try to start it, then work on the mechanical. Find out where it is stock, which is probably way to much and then start backing it down but by bit. Open chambered iron heads seem to like more advance.
Then work on the vacuum advance limits. That will be around 52*’s.

The engine will really respond to this & the car will just jump when you mash the pedal.