Rig for testing crankshaft endplay.

I took the flexible bracket off of a safety guard (like on a drill press or bridgeport) and used it to hold the dial indicator. It's attached to the engine through one of the mounting bolt holes. It works like a charm.

Looks like it works great. Starrett makes magnetic bases with a flexible thing that you can mount a dial indicator on, and put on your workbench to do the same thing. They're quite expensive though, so like your idea much better lol.