Vance,
okay so let me get this straight.........you want to maybe bore maybe stroke and also disrupt the relationship to atmosperic pressure on your small block? There seem to be a lot of maybes and a shortage of info.
What is the motor to be used for? What vehicle, trans, rear end and ratio? There are a lot of variables and measurements that you NEED to understand before buying parts.
That being said....you did fine on the four bolt block. It is my opinion to buy all of my internal parts new from a local distributor, ebay scares me but it is up to you. Once you finally decide on the rotating assembly you need to mock it up. Check things like the piston to deck measurement for your squish area and also if you are out of square. CC your heads and have the valve job done. Work the math and get direct measurements..........
This is just the tip of the iceburg and you can never get enough knowledge but you can gain understanding if you slow down and learn how to do this right. Beware the magazine sales stories and the drunks at the bar, if you really want to know check out the guys who are running at the track. Ask a lot of questions and don't buy anything until you know exactly what it is you are trying to do and why!