70's Hein-Werner
My brother and I ran Hein-Werners in the late 60's to mid-seventies. They were a fairly popular machine in Michigan, being one of the first manufacturers to produce what was then considered a big machine. They were somewhat slow but powerful, no fancy pilot controls you know. I notice yours has the later undercarriage which was a step up from the first one's. They were simple in design and the Detroit, though loud, was usually dependable. Our worst problem was hydraulic leaks and blown hoses. And we never could keep the bucket pins tight.
Can't tell you much more than that, the dealer in Michigan was AIS out of Grand Rapids. They are still in business at least.