Slappy, since the things that make a Feather Duster a Feather Duster are the hood, trunk lid, bumper mounts, intake and exhaust(all lightweight stuff) and it sounds like some of it is gone. I just sold a trunk lid recently from a Feather Duster and got a whopping $75.00 bucks for it. If the car was all there it would be well worth the $1500.00 bucks. Since it has a big block with it that brings it back to being worth about what he is asking BUT!!!!! Car still has small bolt drums all the way around, 7 1/4 rear end, no tranny, no front seat, needs lower quarters, and you do not know the status of the motor. Do the math. Unless you are planning on spending lots of time on the car and considerable amounts of money finishing it maybe its not worth it in the long run. On the flipside if you have the time and money if you were to search and find front seat, a slant six, (and there are LOTS of date coded 76 slants around), get another Feather Duster trunk lid (or Dart Lite) and bring it back to its original glory it will be worth some bucks as they did not make too many of these cars.
Bottom line as far as I would consider the big block is worthless to this car as it would only bring the value down. Remember, you will need conversion motor mounts and still have to notch the K member for the oil tube, get a tranny, an 8 3/4 rear end, torsion bars and complete heavy duty V8 brakes all the way around. LOTS OF MONEY. The other route is a seat, a six banger and tranny, and some good old body work. LOTS LESS MONEY. If you have a place for the car to sit dry this may be a good find but I would try to deal without the motor. My price cutoff would be at $800.00 for the car alone. One point of interest not covered. Does this car have the 'space saver option? Thats the fold down rear seat, sunroof(additinal option), split high back bench seat. Also does it have an in window rear defroster, dual rallye or standard mirrors, wheel lip trim, 4 speed stuff still there?? These are also things to consider on the worth of the car. Most of these cars were stripped down pretty good but some got the add on treatment and are much more rare due to the amount of options verses the numbers of cars made. These cars did get close to 30 mpg on the highway! I do not decode numbers myself but try and find the build sheet or take the info off the fender tag and do some numbers crunching. Hope that long winded reply helps!!
Chas.
