Many pardons if this question has been asked and answered before but my search hasn’t been successful in giving me the answer I’ve been looking for. I have a ‘54 3100 with the original 235 with a bypass oil filter. The block and filter are both 1/8” pipe thread. I was thinking of using copper tubing for the lines, same as the oil pressure gauge line that tees off of the same port in the block as the oil filter supply line. The oil pressure gauge line is 1/8” copper tubing but that seems small for filter lines. What is the minimum size for these lines?
Thanks,
Doug
Last edited by Izzy1414; 04/25/2026 8:32 PM.
