Thin cylinder walls = prone to overheating myth or not?

I'm sure everyone who has been around old cars has heard the tale not to mess around with engines that have been bored over too much as that can cause them to overheat. In my mind, as small as it is , the amount of material removed between a .0.30 over block and say 0.60 block seems miniscule in the big picture so perhaps this may be just an old wives tale that clings to the hobby even today?

It would seem that a block with thinner walls would transfer heat into the water jackets faster and therefor run cooler? Perhaps the thin wall block actually puts heat into the water jackets too fast and the cooling system can't keep up?

The block with the thicker walls would retain heat longer as there are more metal molecules in play. To me this would be a slight negative as the heat transfer process to the water in the block would be slower vs a thin wall block.

Anyone ever have any real world experience with rebuilding an engine only to have it run hotter afterwards?

Discuss?

As thin as the BB mopars are with a standard bore, I would say it is mostly a myth. to thin just cracks

From a thermodynamic perspective, it's a myth.

I have heard of a couple engines running a slightly hotter (10 deg or so) after a fresh rebuild, but their owners and I attribute it more to new bearings and tighter clearances--not thinner bore walls.

In both cases after a few hundred miles, the engine temps returned to "normal".

This theory would condem all engines made in the last 35 years.

Increase heat tells me the motor has more friction due to the fresh cylinder walls being rougher than before the rebuild, especially when it goes back to normal after break in

This is my take on this topic. Think of the cylinder wall as a layer of insulation between hot gasses and cold coolant. The thinner the insulation, the more heat transfer will occur from the hot side to the cold side. Thermodynamics says the cold side (coolant) temperature will increase. But is it significant? Who knows. I'm not going to attempt to quantify it.