Lets see some Marine Air Cleaners on Hot Rods! Have a wanted add on the HAMB for one more of these but lets see what diff. styles there were. Thanks!
Probably not actual air cleaners but likely flame arrestors to prevent any backfires from igniting fuel fumes in bilge. Still cool looking.
O'Brien Truckers make 2 barrel versions https://www.obrientruckers.com/air-cleaner-2-bbl-spark-arrester-style.html I have 4 barrel versions
I have been running this one on my ‘32 for the last couple years. The 2 four barrel ones, are just hanging around for right now.
Having one of the round ones like in post 7 on the 350 in my Bayliner I would say that is what they are far more than filter. There is no filtration material in the one on my boat.
I've got 5 or 7 of those type but only one is that larger one, it's good for the rear of an inline 2x4 setup, to breathe around that front one. I would like to find another large one though to make a pair.