The late 12 Port Charlie Baker was a pretty good mechanic and craftsman. He was in a wheelchair most of his life but managed to become a lifelong devotee of old iron and speed equipment. He made patterns for casting aluminum side plates, valve covers, timing covers, 12 port GMC heads, all kinds of things. His business was called vintage design and development and he was one of the founders of inliners international. He was a pretty good machinist. In fact, Charlie machined up the 302 rods I run in one of my 261 chevy motors and I have one of the few offy knock off side covers he made for the 235/261 chevys. So he was not just some crack pot expressing an unfounded opinion.
I am not terribly versed on gmc motors. But this same conversion can be done to a 235/261 bypass motors. That being said, I don’t know which GMC blocks or year motors were full flow filters or bypass filters. His tech tip was designed to take a bypass filter motor, which bleeds off a little oil from the main galley, ran it through some relatively small lines to a canister filter, filtered this dribble of oil, and then the clean oil was dumped directly to the pan where it was instantly diluted with dirty oil, and change it to a full flow system where all of the oil was pulled from the galley, filtered through a full flow, easily obtained, spin on oil filter, which then redirected that clean filtered oil directly back into the galley, as opposed to the pan, supplying nice clean oil to the bearings and the rest of the motor.
While there are opinions on both side as to the propriety of this modification, it is still a viable method to convert a motor from a bypass filter motor to a full flow filter. And frankly, there is a third option. Don’t convert and don’t run a filter. My 235/261 motors are all heavily modified and I don’t run a filter at all. I just change the oil frequently primarily because I don’t get a lot of miles on my vintage vehicles in the course of a year. And make no mistake, I am hard on my motors. Is one option better then any other, I don’t know, but like I said lots of opinions.
Roll your sleeves up and dig in. That 302 motor is one really great motor and truth be told, it responds to all manner of hot rodding. You still see some of them being run at Bonneville. If you don’t want a stock 302 motor, then don’t build one. Build what you want. Register for the inliners international bulletin board and ask your questions. There a still quite a few very knowledgeable 302 guys there if you need or want a second opinion.
