Clarification.... If the pin is pushed in you won't be FULL PRESSURE/FULLY RECIRULATION filtering the oil, it'll probably still 'bypass filter' a little. Whether the pin is IN or OUT you've got to have a line from one hole to the other.

'51 Chevy 1/2 ton w/'62 261, HEI, offy, fentons, dual carter/webbers, t-5 & 12 bolt posi