1" is the best you can get. It was made by GM for their racing division. They pop up for sale every once in awhile for the average cost of $2000. I've never heard of one failing.
5/16" chains snap.
7/8" chains stretch after awhile.
The lack of a good chain is the main reason you don't see more turbo 3800s. Some are content replacing their 7/8" chain every 10k miles and others are content on replacing their stock trans with another stock trans when they finally catch traction and pop something.