Carrying the torque of the four center cylinders on a single main bearing was the flathead's downfall. That became especially critical when another 3/8" or more of stroke length got added to a design that was on the ragged edge of disaster to begin with. A broken crank at racing speeds pretty much hand grenaded the whole engine!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!