May Purchase this 73' duster, need some help!

Fifth digit in the VIN "G" makes it an original 318 car.
I did see some floorboard rust there. Patch panels are in this cars future.
One way to assess value on a running driving car is to look at what finished cars are selling for THEN deduct what the repairs of these cars are going to cost. Green isn't near the top of desireable colors so consider that. A 318 car with a 340 in it isn't a "clone" unless it has all the other components that a real 340 car would have. The 7 1/4 axle will live behind a 318 for a long time if never pushed hard. Same goes with a 340. Where is the fun in THAT though? It is the stresses of rapid starts that kills the 7 1/4" axle. Accelerating fast from 30 mph and up will not hurt it nearly as much.