Well if you don't crack the eggs they roll around in the pan.

How's your vacuum advance working? If it's hooped you could be running with late timing and not knowing it, just the initial and mechanical.

When I finally got my 428 put back together I set the timing to 29 degrees [best power on the dyno]that gave me only nine degrees initial. The thing ran very hot at idle and made my clothes stink. I put on a new vacuum advance can and connected it to manifold vacuum rather than stepped. It ran cooler and the stinky exhaust quit. You would have yours set higher than that though. Just a thought.