I tell you how I do it. I determine all the sizes I need first. Then I goon eBay and search for older NOS hard parts like bearings and rings and lifters. I want older parts, because they're made in USA and normally they save money because they've been sittin "somewhere" for a long time and somebody's want to get rid of um. I buy all of my gaskets and seals new though.
If I were you, and you're going to use this car for a daily driver, I'd leave the 170 in it. They have a cube handicap, BUT, they also have a much lighter rotating mass and they spin up a lot quicker. That makes for a quicker and snappier ride.
On the flip side, if you're going to add some hot rod parts like camshaft, a two or four barrel and batter exhaust like an opened up stock manifold or a header, illed head for more compression and other go fast goodies, like higher numerical gears, I would opt for the 225. The bigger cubes will more readily take advantage of modifications. But trust me, a 170 in top tune will put a smile on your face. I speak from every day experience.
