Then I would leave that 170 in there. One thing I would do outside of stock would be mill the head .060" for some added compression. Even in stock trim, that will add some spunk and still be pump gas friendly. It will also assure you have a good, flat head surface. It also wouldn't hurt to do a skim cut on the block and get the deck square and straight and true to the crankshaft center line. I would only do just enough to clean it up, because the 170 is essentially a zero deck height engine. Chrysler's deck heights are notorious for being tall and crooked from spec, so I would make sure to have the block decked just enough to straighten it. That and milling the head will add some cost, but it's money well spent.