The small front axle and non-drilled brake rotor peg it as a '74, and the Bing carbs are /6.
It's a Frankenbike for sure, but that's not necessarily a bad thing. If it's in good running shape and there is some decent maintenance documentation, then I'd give $1,200-$1,700. I'd have to hear it run though.
"Nearly all men can stand adversity, but if you want to test a man's character, give him power." -