Your post is a good example of the difference between objective and anecdotal evidence. Here's what Wikipedia says on the subject:
"The intake manifold fed both banks from inside the vee, but the exhaust ports had to pass between the cylinders to reach the outboard exhaust manifolds. Such an arrangement transferred exhaust heat to the block, imposing a large cooling load; it required far more coolant and radiator capacity than equivalent overhead-valve V8 engines. Ford flathead V8s were notorious for cracking blocks if their barely adequate cooling systems were overtaxed (such as in trucking or racing)."
I grew up with these engines; my parents owned one and so did many friends and acquaintances. The Wikipedia article is right.
