Fox 2 in. .325 .540
Fox 3 in .375 .6 .825
Brodak 2 in. .425 .610
Brodak 3 in. .470 .7 .935
Brodak 4 in. .470 .680 .920
The Fox bellcranks are moderately soft aluminum. Never seen one break, but they can bend, which actually is a plus, since it acts as a cushion.
Just got some of John's bellcranks in. The 2 in. one looks like opaque nylon. The 3 incher appears to be straight, unfilled nylon, and the 4 incher appears to be a fiberglass-filled black nylon, similar to many plastic motor mounts. Haven't pull tested any of them to destruction. The most likely problem with any molded crank would be internal flaws that won't show up until it is pulltested. The 4 inch one is certainly stiff and strong enough by a quick hand pull test.