I don't expect this would get a ton of hits, but was wondering if anyone would remember anything about these.

They probably made more than I have been able to find esp. if we include 4500 stuff and Mag, but I wanted to limit this to the more common 4150 aluminum ones out there.

First-1911 casting, quite a bit deeper under the carbs than usual (this is the one I have, mine is not polished).
Second-Another 1911 casting, much shorter
Third- 1991 casting which is somewhat different but looks similar to the shorter 1911.
Fourth- 1991D casting, which I have never seen before. "D" for "deep, maybe?




Anyone got any old catalogs, or can you remember anything about all this....

Any particular one considered "the good one" or newer/better?