I figured the '70 would probably bring between $4,500-$5,000 and the '72 would be between $2,000-$3,000. As long as the floor pans and frame are solid on the '72, someone looking for a larger project would probably take it on for probably $2,200-$2,500 for a fair price. (assuming it'd take about $18-25K to do it up nicely with another engine.) I'm gauging these figures off what I've seen on eBay as well as how much I paid for my '73 Challenger almost four years ago.
Barracudas & 'Cudas are bringing more money from '72-'74 than Challengers of the same years, so assuming I paid $1,750 for mine in project form, your '72 should bring at least 1/3 more than that.
