having read thru your other replies, i'm still firmly in the small block camp. it'll be the cheapest, easiest way forward and you'll realize and easier sale with potentially a little money on the back end.
don't let the old farts around here get you down. they can be a pretty salty crew, but it's a really great group of folks (most of the time), and you won't find a better collection of people that know the in's, out's and what-have-you's and are willing to share that info anywhere.
**** man, i'm more than double your age and they still think i'm a youngster-- even though i've been a mechanic for 30yrs.
being a greenhorn with mopars is especially treacherous: everything is more expensive and specific than ford or chevy. parts are more difficult to find. buyers are more fickle. even the weirdos who are dyed in the wool mopar nuts are weirder than other makes (well, except for AMC or jeep guys, but they've all hit their heads too many times). it's a steep learning curve and it's certainly not for everyone. but there's a reason for that, mopars are the absolute best vintage cars.
anyway, i'll leave you with this pearl of wisdom: if you really want a big block car, buy somebody else's project. you'll probably still not make any money on it, but at least you'll be able to scratch that itch without going entirely bankrupt.