I always wondered why the full flow conversion was so popular. Well I am now working on a non GM motor from 1957, which has a full flow filter from the factory. It peobably has 100 K miles on it and the bearings are worn and showing a lot of clearance. However the surfaces are just about perfect looking, including the crankshaft. Now on the 216s that I have redone and driven, the bearings never looked that good after some use. So I think having a full flow filter is a huge advantage. If I ever rebuild a 235 or a 261, I will for sure include the full flow modification.
