Build or buy a clone Hemi Dart

agreed - a 426 Hemi will set you back what, the better part of 30-40k depending on what you get.. then you need a donor car - 5-15k depending on condition.. no wrenches turned yet and you are already into it 35-55k.. I suppose if you wanted to do a "rat" style Hemi Dart clone you might be able to get it done for closer to that 50k - but it'll still be hard to do..
I don't think you could do either with that budget and come away with a nice car.

LO23 Hemi Dart