Timing chain recommendation

how often did Grumpy rebuild and change that plastic gear ? I have 3 plastic gears and chans hanging on my shop wall , all with under 30,000 miles







'

I just did an internet search. The "story" was that they changed the sets out after every race. I think it's urban legend BS. Nobody else did that stupid crap. Dick Landy ran as state of the art parts as money could buy and he routinely spanked Jenkins' butt. You think Jenkins was runnin stock nylon coated crappola having to race the likes of Landy? I ain't buyin it.