Used on B-17 and B-24 - one of several types as produced by various manufacturers (most notably GE) during WWII. In fact, if you'd compare it side by side with the turbos for the P-38, P-47 and B-29 they all look like the same beast - lumpy, ugly and heavy. Big old blob of cast aluminum and stainless steel.
Fragile items on the turbos are the hot section and bucket wheel, which are prone to cracking during use or man-handling. This is one way to identify whether or not you might have a candiate for a re-build. Ditto the "feel" of the bearings and whether or not the wheel spins freely without binding. These are the major factors in determining "value" to people like us working on old airplanes. I suppose even a "junker" with cracked or worn parts is of value - they aren't making them any more and at the very least it's something interesting to look at from a museum or collector perspective.
I've worked on a lot of these over the years and could help you with more information (or parts) if you wanted to save it or perhaps even use it. They're a big old air pump - in fact, I saved many of them years ago that were used as grain elevator air cycle machines in the mid-west. That's one of the more clever uses of WWII surplus aero parts used in the civilian market.
Drop me a PM if I can be of any additional help. Good to have you on WIX - I, for one, appreciate the new guys and gals out there finding parts. Now go about in your area and find me some Lockheed PV-2 bits and pieces, will ya?