Here's another tractor:
Just A Car Guy : best thing you'll see all day, the '59 Massey Ferguson of Ardbeg Whiskey racing a classic Lotus Gran Prix race car
Each straight pipe on the blown big block had a tractor flapper valve. At idle it must sound like castanets. There's a video of it on Youtube named
Ardbeg Hot Rod Tractor, but Youtube wants people to sign in to view it so I never will know; but you can search by name. Since I can't preview it, I won't post it here.
http://justacarguy.blogspot.com/2015/10/best-thing-youll-see-all-day-59-massey.html