170 or 225?
I have had plenty of 225s over the years, just built my first 170. Haven't run it yet so not sure how I will like it. 225 gives you more cubes, more torque. 170 should turn up faster. Cost the same to build them, maybe more to build a 170. Maybe it depends on your use and plans for it. 225 might be better choice unless you want all original.