[H. L. Chauvin]

Also, just another humble and "simple" hint to add to reply no. 12 above:

1) If the engine re-builder is not you, and is not far away, he should have a "quick" clue to your engine problem .... that is .... if he knew what he was doing in the first place.

2) Could be worth a try to contact him prior to spending more money and spending time investigating and changing out thousands of individual Model A components and Model A parts.