I just thought I would post this again......A book is worth its weight in gold.
A book I highly recommend is HOW TO BUILD MAX PERFORMANCE SMALL BLOCKS ON A BUDGET ,by David Vizzard .
This book goes into all the questions you are asking in great detail and it also gives a list of good factory parts to use and ones not to use.With this book you could probably save a couple hundred bucks on your engine and get 100 more hp out of it.... not that I am discouraging you from using the forum , I am trying to better enable you to get the answers you need by being able to ask the right questions.You are asking lots of questions which is good,thats the way to learn.
This book starts with a regular stock engine and using stock parts and adds power 1 step at a time exsplaining how one part effects another each step of the way,if the book was not so darn useful I would send you my copy