Chevy made 2 14bolt axles over the years, one being a 9.5" ring gear, which is what that looks like, and also a 10.5". The 10.5s were used under 1973-87 3/4-tons, and are easily converted to run disc brakes with a caliper bracket that Modern Motors even has in stock. (I had mine converted and it works great!)
The 9.5" ring gear models used in the rear of 1964-and-later GM pickups, and in the rear of 1984-91 3/4-ton Suburbans. This one looks more to me like a 9.5" version. The bigger 10.5 ones have a very unmistakable shape to them being a lot more angled. This one seems a bit rounder. I'm not sure if they are a full floating axle or not, but the 10.5 definitely is.
9.5"
10.5"