I really don't like the 140 reading, but if it is relatively even across the cylinders..might be stuck with it for now

Definitely shoot the water under the manifold too...you never know.

I have had the gasket between the baseplate and the main body of the carb fail, and it actually had an internal vacuum leak to
one of the barrels of the carb, and really ran strange. I couldn't have found it if my life depended on it, no testing showed
anything until I took apart the carb and there it was.

Questions

If you goose the throttle to 3 or 4000 rpm and let it come back to idle on it's own.....does it immediately snap back to idle rpm,
or does it slowly come down from the higher rpm point? If it comes down very quickly, it is probably not a vacuum leak and I'd start looking elsewhere.

Is TDC on the balancer 100% verified correct, by you personally (since you're tuning it)?

What kind of a timing light are you using?

Sorry if there's any redundancy and these things have already been mentioned