K&N Air filter for Universal 5432/M40 is RA0500

About four years ago I upgraded the air filter on Aeolus to a K&N model. The intake manifold opening is actually larger than the air opening on the stock air filter that came with the engine. So to improve air flow as well as accommodate the PCV system I installed, I switched to the K&N. Some time back I was asked by a follower of this blog which model K&N it was, and I've finally remembered to post it.

This model fits perfectly and does the job. Here is a link to the K&N site for this model:K&N RA0500