[Synchro909]

In my most used Model A, a 1929 Phaeton, I run inserts with just the middle one pressure fed at 25 psi. It has an oil filter on the side cover and an air filter, 5.5:1 head, downdraught carburettor and mild touring cam. I have put about 40,000 miles on it towing a camper around the outback. I am just now staring to hear the bottom end pounding away under full throttle so I will soon be pulling it down and doing whatever I think it needs. I expect to find the middle main bearing worn but considering the miles it has done and how they have been done, I am not complaining.
I have a friend who does similar trips towing a camper behind his 1928 Chev with babbit bottom end. He carries a spare con rod with him and adjusts the mains every few thousand miles. Clearly, my inserts have stood up to the demands better than his babbited engine.
PS Re oil change. I watch the instruments and when I see the oil pressure droping for the usual 50mph and 180F, I change the oil. That is a regular 3,500 miles using the cheapest oil out there.