Another idea I had for my 68 which came with the Donaldson Oil Bath air cleaner was I noticed some of the mid 70's GMC medium duty trucks with 366 or 427 V8 4bbl came with the same exact style air cleaner other than the fact that it had the larger base. If I ever go that route it will be mostly for display, I really like the amount of air the 14 inch K&N air cleaner takes in