They made 2 different oil filter adapters. The 1 from my original motor faces the rear but this 1 faces to the front & is 70-up. I am going to run headers but there isn't room for the oil adapter so I have to use the std filter set up. The #2 & #4 mains feed the cam & then it feeds the heads. The #4 feeds the PS head & #2 feeds the DS head.