My machinist, who was a very detail oriented machinist I trusted with my machining, told me he wouldn't use Cloyes because they stretch too much for him when he tears them down for a refresh for the season. He built a lot of race motors, some stock motors and everything in between. Unfortunately he passed away of cancer last year.
He usually used ProGear by Avon Gear. I specifically like the 4000 series, billet 9 keyway sprocket, torrington bearing, etc. They are made in IL, but they are hard to get. He said they would have barely any discernable stretch during the refresh. They can be a little more expensive, but not too bad.
I sell Howard's the most because it's a USA made billet steel 9 keyway sprocket and a USA made chain, also with a torrington bearing, for a good price. They also have them for a lot of different engines. I like the 9 keyway models because you can move the cam timing within 2 degree increments and it cannot move like an adjustable sprocket can if it comes loose. Howards also sells a model with a super tight tolerance chain, but they are considerably more and only available for a select few engines.
I can get these and stock some part numbers...
www.howardscams.com
Also, I think for most stock engines, zero stretch doesn't really matter, you won't feel it unless its quite bad, and too tight of chain can actually cause more friction and loss of power.
Stock GM chains I have measured to have almost a degree of stretch when new! So there is a happy medium on the cost/performance, and I think both Howards and ProGear have their place.
