gmbelt: I have a 1948 w/ a 510A . I believe the set up might be the same. The canister oil filter had a Fram C147...These don't exsist anymore . I tried matching the filter by its size,width, length,dia. of center hole ect. and hydraulic filters seemed to be as close as I could find. My mechanic and cohort said these would work due to the type of oil system on tthe old macks but they run about $15-$30 bucks. My problem on my motor with the NAPA 1503 filter was the outer Diameter of the filter itself. The gasket and center hole fit the tube snug but the filter would drop to the bottom of my canister housing. The inside of the canister had a ridge which the original filters sat on. I used some sheet metal experience and made a disk that sat on the ridge inside the canister that would hold the 1503 filter at the right hieght to snug into the top mounted on the side of the motor. I put some holes in the disk to allow the oil to flow to the bottom of the canister. It is working sofar I have lucked out that in the original gasket still works the one that comes with the 1503 doesn't work but we might have to make our own in the future. Hope this help WECO1MACK505