Mike.
My 1966 C-10 with a 250 has the disposable paper element. I bought this truck in 1994 with 46,500 miles on it, and it was original. I think the oil bath type was used a bit earlier, but I may be wrong. I know that my girlfriend's 1957 Oldsmobile 371 engine has the oil bath type, but that is an entirely different vehicle.
Check some boneyards, you might find the correct one for your truck, but dont't get one later than 1967. I think the 1968 and later ones are different.
Doug 57.
