What later filter types showed up in 1956 on 235 engines?
I agree with truckcamper53, "The best oil kind of depends on the condition of your engine, the amount of miles on it and the climate (how cold. ) where it is driven". Regarding engine oil, multi-grade oils are OK - GM listed them for later 235 engines. I use multi-grade diesel oil and have used 20W-50 oil in an old engine (and even 50W oil in an old engine in the summer).
