Well I am of the mind if its you car and thats what you want to do then do it. I disagree about the new Hemi's in vintage Mopars and if I had a car without a drive train I would definitely do it, especially since a 5.7 is going for sub $2k these days. I have seen vintage Hemi's in E bodies and B Bodies and while It isnt my taste, I don't hold anything against those who do it. I have a 56 Desoto 330 Hemi in a 52 B3B pickup and love it. Granted that's very different than putting one in a muscle car but it is what it is. Having said all this, I would say this based on my own experience; the gen I hemi's are very heavy, parts are hard to get and they do not make power like a more modern engine. If you are going for the look, then you are good, however if you are intending to drive it often you might want to consider going conventional engine or even a Gen III.