On the K&N flame arrestor, part #59-3370 for 500HP carb. Does anyone know the vent kit numbers needed? Will the ones on the Merc arrestor work?

Dean, Here is a link to their marine page. Here is what they say about their marine filters;

Marine approved per SAE J1928 standard
Smoothes and straightens incoming air
Increases horsepower
29% more airflow than other flame arrestors
Washable and Reusable

K&N Marine Filters

29 Fever, that part# you posted is a 9" x5" high. The vent part# is 85-1662 and you probably need two. These are 6" tall vents and you'll have to cut them to fit your height. That's what Im doing.

Eric

Thanks Check,

After your post I've decided to go ahead and order the K&N arrestor / filter. I'll post results.