Wanted 70-76 duster project
Based on what you’ve shared I wish you a lot of luck! Body work (even with minimal rust) and paint is going to be several thousand $.
Depending on how fresh (rebuilt or not?) the V8 and transmission is you drop in along with new rear end/gears, new brakes and then interior, I’m not sure how you are not going to be north of $20k?
[FOR SALE] - 73 Duster project
[SOLD] - 1972 Plymouth Duster $2000 OBO