Put the correct one from Harley on there. Like said, back then, requirements were no so critical as tin men driven filter specs have become. You put one with some very small micron spec and you will loose most of your idle oil pressure. I am not even sure Harley carries one with the original spec. Even mine specced 10 microns and I think Harley's is 5 now. Hope I got that numbers in correct order.

 

EVO filter 63805-80A Black one. 31/4 inch Have a few of them in the bike room.