I seem to recall pulling a '57 235 apart a few years ago that had similarly wierd grinding on a couple of the counterweights. I vote for "its factory"...
going on a diet, it involves the question what do you want- high end HP or low end torque?
Since the head doesn't breath all that great, I'd vote for low end torque and just get everything balanced. If you read through that Huntington book, I believe he basically says the aluminum flywheel and lighter crank are for higher rpm racing usage. A big heavy '49 Chevy needs torque...
