I just converted my oil bath air cleaner to a paper filter element. The oil bath was a two-piece filter
(click) and I didn't want to cut it up, you just never know.....
I found a decent three-piece top on EBay for ten bucks and installed a NAPA FIL 2193. It's 4" tall and fills up the oil bath reservoir
(click). adequately.
Hope this helps, good luck!