There is nothing online anywhere( not even on Champ Lab's own site - it only gives you their filter line part #'s )as of yet for RP filter applications. You have to go to a PepBoys or e-mail Champ Labs. I actually have an RP filter catalog coming from the local PepBoys manager. He said he would get me one. If it ever gets here I can look #'s up for anyone who wants.
However, from what I have seen RP filters mirror Champ Lab's own filter line( Champ )part #'s with either a 20- or a 10- in front. I don't know what makes it a 20- or a 10- though????
Example. My truck takes a Champ PH820 filter. The RP filter # is 20-820. Friend's truck takes a PH253 and the RP # is 20-253.