Almost had one (seven main 170 crank) but it slipped away.
Found someone who had 170 Bronco engines and said they had seven main bearings. Bought the crank and took it to a machine shop to have it checked out. When the throw was checked, it came out to be 3.126" instead of 2.940". Argh! A 200 crank.
Talked to the guy who sold me the crank and he said that the block had three freeze plugs on the side and seven mains. The only thing we could figure out is that the 170 needed a new crank and the 200 crank was the easiest to locate. When he dropped the oil pans on the other 170s, they had four mains. D**n!
So, I'm still looking for a 170 seven main crank. You guys that have 170s laying around, drop the oil pan and check the number of mains. You may have what I'm looking for.
I'm willing to pay $200 plus shipping.