Go-Power Engine Dyno... Value?

OK, so I have an older (70's) Go-Power engine dyno that I've got a guy interested in buying. It has a 600 lb-ft torque capacity and 10,000 rpm limit. It's a small water dyno. The entire rig can fit into the trunk of a typical sedan. Included is all the wiring, cables, hoses, instruction manual, a couple sets of headers with pyrometers installed, gauge consoles, throttle, a tool cabinet, engine stand, etc.
What price should I ask for the rig?
Thanks!
$500?
but to be honest I think it would be more like $2-4k just on the little bit of info I was able to get from a google search. I have been interested in getting one just to play with but have not done the research necessary to know exactly what kinda cost I am looking at. Hopefully someone will chime in that can offer a non-biased opinion of what it is worth then if things do not work out with the first buyer you and I can haggle.





