I know you said 70-73 but I have a solid 74 Duster that spent it's life in west Texas. Send me a PM if you are interested. I also have several parts including a complete A body 8.75 and a couple engines/trans that could be sold separately as well.
The car is definitely worth the time if its a 70 Duster 340 auto. that you want. I have owned this car since the mid 80's. The car was a "Driver" when I purchased it. 90% of the parts are still with it. $6500.00 OBO.
It is an H-Code. It is yellow and has an automatic in it. Originally, it was a 4-speed. I have the 4-speed transmission and pedal and hump are still intact.