If it was mechanical, Diablo, it would take a lot less than 6 minutes to cause a problem . .more like 60 seconds or so. You'd lose a bearing, or seize a piston in a cylinder, or something like that.

One other thing. . the older 5.8/6.2 engines LIKED to rev .. they ran cooler that way for some silly reason. I ran a 26-10 Mejzlik, or even a 26-10N Mejzlik, which is a prop with a lot less drag than a Menz-s 26-10, even though the Menz is 3/8" smaller in diameter. Keith used to really brag about that "6400 with a Menz-s 26-10" quote, but I found the engine was a LOT happier zinging up to about 6700-6800 rpm, and unloading in the air a bit more.

Personally. . I'd run a 26-10 Mejzlik on an old style 102/6.2, and a 26-10N on a 5.8 or first generation 6.2 upgrade. Let 'er spin. . I think you will see a difference, and it will sound OH so good ! !