all my trucks have the fiber gears, 216 and 235 engines between 1949-1953 i just replaced one earlier this year, the fiber gear in my 53 GMC 1 Ton failed, i grabbed a slightly worn fiber gear from a partially disassembled 216 i had handy and put it all back together and it runs better than ever, this engine spun a lot when the fiber gear failed on the highway at 40mph the 235 and 216 are non-intrusion engines, the valves will clear the piston in any position, something out of the ordinary would have to happen to crash a valve the cam shaft also cleared all rotating parts when it was stopped with crank spinning, i did pull mine out to inspect but it was fine and went back in with it's new old gear. -s
