I've seen original 340 double roller chains still within spec with over 100,000 miles on them. I have used an old Cloyes true roller from one engine to another. I got the tensioner bug, a while back but when I thought about it, I'm not going to use it. I have a 273 with 300,000 miles on it with a 340 double roller timing set in it. That engine starts and runs like new. Anybody want a new tensioner cheap?