The 51515 filter is 5.19 inches tall. http://www.wixfilters.com/Lookup/PartDetails.aspx?Part=193964
the 51085 filter is 3.83 inches tall.
http://www.wixfilters.com/Lookup/PartDetails.aspx?Part=160797
Same mounting (3/4-16), same diameter
both have a 7-9 gpm flow rate.

FYI the 51515R is 5.17 inches tall.
http://www.wixfilters.com/Lookup/PartDetails.aspx?Part=76220

Joe

Last edited by sr4440; 04/27/18 12:40 PM.

Without Data, you’re just another guy with an opinion.