I've been told that the diameter of the bolt-head can be used to identify whether it is an A/C or a Fram. If my memory serves me correctly, the 5/8" head is for an A/C filter and a 7/8" head for a Fram.
I'm sure someone will correct me if I've gott'em reversed. BTW....if you eliminate the bypass filter you will pick up 5-7 psi of oil pressure. Full flow conversion is a much better option.
Dave
