I have a 69 Chevelle 454 thats pretty performance oriented and I go with 10W 30. It would be alright in yours, I really doubt your gonna be running it when its 30 F outside. But buy Royal Purple, yes i know its more expensive but it really is the best oil for these older engines and performance engines. It will also give you a slight boost in HP (about 1-5hp) just because of less friction.