The Stovebolt Site Forums The Parking Lot Big Bolts About at my wits end, getting an engine to run

From what you've said it sounds like it pops when the motor is put under load which makes me think it's too lean at that point.
Can you increase rpm slowly and bring it up to about 2,000 rpm without it popping, not under load ?
You said you could drive it around the yard which I take to mean low rpm and not much load.
The mechanical advance should be working as rpm's come up and when you put the motor under load manifold vac drops down and the vac advance is not an issue at that point unless there is a vac leak.
Course you know, I wish I could hear it run....tell me more.
Dan