[Bluebell]

With respect to Jakeford's original question, I would suggest that the centre port design had little to do with block cracks, more to do with deteriorated cooling systems (scale build up and blocked cores etc) Back in the day they worked hard maybe with less care. Most people today running a flathead v8 are enthusiasts of some sort. Sure, my dad checked the water and oil regularly, to make sure it was there, but not so much to eyeball the sludge build up in the rad. Many people were just getting by. 90% plus of engine failures stem from cooling system failures. That is the main reason for cracks.
I am not saying the FHv8 is not prone to cracks. In fact Henry relieved his war time truck blocks for just that reason. Vacuum brake boosters were leaning out the fuel mixture, raising cylinder temps, and causing cracks from the exhaust seat to the cylinder. The relieved block was his answer to the problem.
Just saying that in the day, the design was fine and that it was the things we do (or didn't do) that lead to the cracks.