Ah memories. The first sled I ever took to a radar run was my old mans '77 340, liquid cooled, twin carb, AC Cross Country cat. Great sled and a real screamer for its time! Ran low 70's in 1000'!:0
Anyway, a guy at one of the radar runs we went to had been eye balling it for some time and finaly offered my dad $1200 for it, and that was early 90's. My dad only paid $500 for it when he bought it and that was with a new track and running strong. Needless to say, he didn't refuse!
I'm sure that to the right person, it would be worth a fair amount(even not running)because those are getting very hard to come by now. I would "guess" that you could get around $500 or so even with it not running as long as it isn't too major of a fix. Just a guess though....
Sorry I got long winded, but I have good memories of that sled.