RWT,

I have been doing some research on the filter for the 603. Apparently Baldwin purchases it from Champion Labs Luberfiner division.

In further discussions with Luberfiner, it appears that Luberfiner also purchases the filter for both the 603 and the 617 from somebody else! I could not get them to divulge this info.

I have received the limited engineering specification for the Luberfiner filter for both engines. The 617 appears to be a bypass filter with 242 square inches of paper and it has a 20 micron rating. There is even more limited data in the 603 filter. I have requested Champion to go back to the manufacturer for more data and they agreed to attempt to do this.

I am going to buy a case of the filters for the 603 and see what I get.
What is interesting, however, is that the price for each filter will likely be about $11.00. This is significantly less than Baldwin and about $1.00 less than OE. They have confirmed that the filter includes the O-ring and copper sealing washers.

This whole business of oil filters is fraught with murky dealings between "manufacturers" and "distributors". You cannot figure out who the ultimate manufacturer of the filter really is.