Much thanks for all the great advice and tips while I undertook this project. I've been turning wrench for over 35 years, but these newer engines are getting tricky. The stop block was the ticket. Only $30.00, and at least I don't have to sweat it if the primary tensioner goes south.
Final picture of the engine replacement project. $2,200 worth of parts, but the thing purrs and my son is happy to have his car back after one year. Everyone had written it off, but patience paid off, and I was able to find this new heart for it.