American Racing Equipment now owns the name Ansen, and reproduces the famous slot mag. I looked into them a while back, and found the following:
1. The biggest issue seems to be the center bore, which is too small to clear the front hubs on a Bronco. Some people have had them machined bigger to clear, and I think one poster even did it himself with a Dremel tool or something.
2. American Racing doesn't seem to have any interest in answering questions. No link to contact them, and the web site just says "see your dealer." (Ideally that dealer would be familiar with Broncos and would order one wheel for a test fit.)