Timing chain oil slinger

Snowmobiles use silent type drive chains...so it is not a matter of strength per se. But they stretch a lot more and you need to adjust a new snowmobile drive chain after a few hundred miles, and then again regularly. They just tend to stretch a lot more than better chains (due the materials I am gonna guess). No wonder the above engine has a tensioner; I imagine they use the silent chain for noise levels but need to keep it from flapping around too much. That is a much nicer looking setup than the simple sprung chain tensioner, and looks very much like the better setups I am used to.

I remember that Chevy 350's had a common issue of the silent chains stretching and flapping around so much that the slopping around would literally wear through the lower right hand corner of the stamped timing cover and you'd have a massive oil leak. I recall epoxying up a timing cover on one of my wife's cousin's 350 so he could get home to Nashville...I'm sure he never had it fixed beyond that LOL

And FWIW, yes I do build with durability in mind myself. If you spend $1500-2000 entering and towing 500-1000 miles to a rally, having something break in the event due to cheap parts is a really bad day.