It is sounding like 470 is a happy medium to go to. I'm sure this will be more than fast enough for me for now. Especially coming from my "fastest" vehicle going a 13.9 in the quarter. I will mull it over for a bit with my cousin (has built a stroker for his duster) and the guy doing machine work about going bigger than that.
I will probably wait until December to buy all of the parts, in anticipation that some businesses will have some sort of christmas sales.
Our truck is broken for the moment so I can't pick up the block I found yet. But its apparently a standard bore 1973 motor.