I could be wrong (it happens a lot
) and I'm sure the factory guys know what they're talking about but a 42" shaft on a 170CC seems a little short. I'm sure it would be coming out of the water with any kind of wave action. I wouldn't put anything less than a 48 inch on the bow of a 170CC. Of course, that is just my opinion based on my experience with my boat and the water I fish...for what it's worth.