what oil to use

:axe:This thread is like the Greek mythological figure the Hydra, each time you cut off one of it`s heads, two grow back in it`s place. Lol! Here`s something that may help the oil issue being discussed here. According to Chryslers original factory service manual for `68; "whenever an engine is rebuilt and a new camshaft and/or tappets are installed, add one quart of factory recommended oil additive to engine oil to aid engine break-in (Engine Oil Additive No. 1879406) or equivalent. The oil mixture should be left in the engine for a minimum of 500 miles, and drained at the next scheduled oil change." Hopefully this should shine some light on the need for the zinc additive at break-in as a prophylactic but also lends itself to the fact that after break-in it`s not necessary. Years ago though there was leaded gas as well as other metals like zinc and magnesium in higher concentrations in oil and gasoline to help "lubricate" the engine. We must do what we can with what we have in these modern days with emission controls if we still want to run our dinosaurs. There you go, that should cauterize the Hydras neck, at least for the next five minutes.