These saws were big, heavy, torquey beasts.
Displacement is 111cc, 7.0 H.P. max @7,000rpm. Max engine speed is 10,000rpm.
Dry weight w/ a 53cm bar and chain is 11.7 kg. (about 26lbs.)
Almost all parts interchange with the 076, and other than a smaller displacement (smaller bore cylinder) they interchange with the 051 as well. There are lots of these saws around and parts are pretty easy to come by. In fact, there hasn't been a new I part I needed that my Stihl dealer hasn't still been able to order for me, and I've needed a lot.
Price varies. On ebay, they seem to go for ridiculous amounts. How much is the one I assume you are looking at?