have some questions about 350 performance parts

[ya it is a classic]

hey guys thanks for all the input! ill look into the parts you guys recomended and ill make a list and see what you guys think. also winola73 i would like to keep a manual in the pickup. and yes i have the sm420. i was thinking 5 speed. can i steal one out of a newer pickup? also blackedoutharley you said keep the manifolds and just run exhaust depending on the numbers. would that give me as good of HP as just getting some long headers? also do i want straight pipes or mufflers? and im assuming dual exhaust. right now i have the manifolds and a 2 into 1 pipe with about 3 feet of 2.5 pipe behind that(no muffler of course!) now i have enough pipe to not mess up the valves right?
thanks for putting up with my questions that are common knowledge to all you gear heads. i really appreciate it!
-chad