I thought I had created a post about the various oil filter brackets years ago, but if I did, I can’t find it. So, here are the three type of brackets on l-heads from 1942-1965. (If anyone knows of others, let me know via the comments)
Triangle: The first type is the “triangle-style”. It’s a familiar one on WWII and CJ-2A engines.
OVAL: This second type, the “oval-style”, was likely on l-heads sometime and somewhere between 1950 and 1952 (as best as I can tell). These are pretty rare and the pic below is the best example I currently have.
Round: The third type, “the “round-style”, appeared on late 1952 l-heads and later on DJ-3As:




























