Re: K&N air filter for 59 FL
Without checking your K&N part number, I can say that YES, there's a K&N filter that will fit in the stock air cleaner. But only the later ones with the center screw like yours. The filter is a tad too thick to work with the J-slot cover--- but I've heard of a few guys that have successfully trimmed the filter down to fit.
But with your air cleaner, it will fit. However since the filter is a little thicker than stock, part of the backing plate will show, about 1/8".
59 Pan/Knuck Chopper
77 Stroker Shovel FLH
94 Evo Secret Components