Eastwood ZDDP Oil Additive 4 oz.
Product Review (submitted on June 5, 2013):
I have a 1972 & 1975 Corvettes and found out that I needed to add ZDDP to the oil. look at all the Auto Parts Stores and they didn't know anything about adding ZDDP to the older engines because the oil companies took the Zinc out. A must have