When heading from Sutrio to Ovaro, long before reaching the top, there is a parking lot on the right side of the road. Do not turn into it thinking it is the continuation of the road, instead make a left turn and continue up the mountain road.
On the way down from the mountain top to Ovaro, there are three narrow stone tunnels.
This road is very narrow from the parking lot mentioned all the way over the mountain to Ovaro.
I have taken this road many times and they recently improved the section through the tunnels. The road surfaces within the tunnels are now paved and there are overhead lights in the tunnels.
This road is on Google Maps Satellite Street View.
This is probably the most amazing small route I have been on. It is 8kms of 1st or 2nd gear to the top and plush ski resort on the way down. There are a few short tunnels on route but beware they are NOT for the feint hearted as they are dirt and stone inside the tunnels but tar the rest off the way. It ends up at the TOP of a Giant Slalom Ski run and is so different that I had to p[ost the route here. So if you are in the Ampezzo Dolomite region give the rout a go. I will try to post a picture of the road profile. The route is best run from the 1 to the 2 way points and not the other way around.
Paul-K