Any good tips for firing up motor on engine stand?

No one mentioned the hook up with an automatic transmission. Does one need to fill it with transmission fluid? If so, wouldn't fluid poor out the tailshaft?

I filled the converter and dropped a couple quarts in it. I ran the engine long enough to break in the cam , about 30 minutes. I secured a yoke in the tailshaft and made sure it was in park, ran a rubber line from one coolant line to the other. never leaked a drop. if I had had a different way to mount the starter I would have , but it worked out just fine using the A/T