What's your opinion on the slack in this 318 timing chain?

The spec distance seems to be 6.125 inches. Cloyes has race billet sets for 6.120 and 6.115. I don't need a race billet with adjustable sprocket, but I would entertain an affordable set for 6.120 just to buy and try. But who makes them? Who sells them?

Are belt kits available for the 318?