Here is what we've been using up here for a number of years now! It has seen likely 30 or 40 engines. We have many square backplates now with various engine mounting patterns. I have ran 20cc right up to 250cc Mokis, 210cc Valach, 220cc piped quads.
It's currently got a Moki150 flanged to it with a Moki257-7cyl coming up next week
http://www.rccanada.ca/rccforum/showthread.php?t=71376&highlight=Test Stand
Hopefully this fall, I'm going to build a new stand. Similar configuration with a few improvements...
* On a drawer slide system to be able to measure pounds of thrust
* Motor mounted inverted so that headers are easily accessible during header length adjustment/pipe tuning
* Telemetry with a possibility to measure engine spool up (a custom telem module)
Cheers
Trevor