<VV> Corvair 110 sounds like 10 lb hammer

[chaz at properproper.com]

The interesting symptom is that there is no noise or any issue without
being under a load (i.e., running)

Since there's no noise hand-turning or cranking with the starter, the
problem is caused only under a load?

My proposed test procedure:
---------------------------
Tomorrow, I'll try running her a few times as a 1-cylinder engine with
only one plug in each cylinder at a time (if she'll run that way, to
hear the banging under a load, to ID the offending cylinder?

If she won't run as a "1-cylinder engine" then I'll try as a "2-cylinder
engine" with 1-2, 3-4 and 5-6 and listen for the noise?
 
I'll check the harmonic balancer and flywheel for loose parts too ...

Thanks for the ideas!
Charlie