Here's a basic question that I could not find in the archives. I understand that the paired oil filters in the 4 liter Columbo engines (as in the 330 GTC) are not identical, one being a bypass filter with a finer particle size. Can you still get the 2 types of filters; from what source? I also understand the commonly found Fram filter has a bursting strength of only 200 psi and the specs call for 500 psi. What do you guys do? Related to this, I read warnings against multigrade oils in these old engines, any thoughts?