V/8 Swap

Is it worth the money and effort to V/8 a A body mopar? I'm asking because I have seen some 6 cylinder cars that are in good shape, no rust.I did find a real clean 1974 duster for 29k. It's a 318 with ps, pdb, ac, is that a good price or outta sight? A classic car dealer in Illinois has a 1973 or 1974 duster that's in awesome condition but they are asking 41k and I don't think that it's worth that.
29K for a 74 Duster would have to be in excellent condition. Id stay away from dealers myself
I think swapping a 6 for a V8 is ok depending on the car and it your doing the work yourself
You should be realist in what you can afford, related to what you'd want