If you want something fun to drive and you want to hopefully break-even when you get out, go for a '72 - '74 'cuda and do it up the way you like. IMO, if you stick with factory type parts, you won't hurt yourself on the value. For example, drop a 440 six-pack in a '72 'cuda....not going to hurt the value much, so long as it looks factory. drop a chebbie motor in there and kyou will immediately be stripped, painted purple, and beaten with a large stick. :spank:
I can tell you that I am more conscious about my car's value than I probably should be. I should spend the money, have fun, and build what I want. Am I going to be a little upside-down at the end of the day? Probably, but nothing's free!