1970 Ddge dart swinger 360 engine questions

I don't know what cam that is (book is out in the garage and it's -4 out side). Why do you want to run old 340 pistons? You can get some new ones for not much money, and get them for the deck hight you need. For a street car I would say run the dual plane intake, with a 650 cfm carb. If you want to run a bigger than stock cam (ie 284-484) you will want to look into a little looser converter. Go with 2 1/2 inch on the exhaust, same basic price and you have room to upgrade. As far as power, it all depends on the parte you pick, and how they work together.