73 Dart Sport 340 help

Can anyone give me some info on these cars. I am familiar with the earlier models, but not much on the 73's. I have come across one for sale, it's a 73 340 with a pretty good amount of rust. It came with the original sun roof/vinyl top so the roof is rusty, floors, quarters, etc. It still has the bucket seats and has the original top banana yellow paint. The original motor is long gone, and the 318 currently in it does not run.

What rear end and transmission would have came in this car?
I know in general 73 aren't as popular as the older years, how about the 340 cars?
Is it worth $800?

I have a tendency to buy a good deal, never get around to working on it and my wife tells me to sell it. I guess what I'm trying to get at is...is this a good deal?