thats a lot of initial timing, but you might be ok with it. Are you getting run-on after you turn the car off, or is your starter turning slowly or getting kickback? Sounds like a carburetor problem. Pull your plugs and read them!
I'm assuming two things can be causing your problem:
In the carb your pump shot or transition circuit could be too agressive. A lean condition would be heard as a "pop" coming from the carb. Rich is usually a bog. A less agressive squirter or pump cam may be necessary.
You can also try to bring in your advance more quickly. Maybe run a couple of degrees less initial, but make the mechanical come in more quickly by changin the springs to a lighter set.
When does your mechanical start coming in, and when is it done?