Vette(s): 1982 C3 Collectors Edition 44000 miles, sat in the sun most of it's life, My wife purchased it for me for fathers day in 2007 from her girl friend that had it for 19 years. It is on the road again. I'm retired but it is now my daily driver.
I did some reach and for flat tappet cams engines you need to be concerned with zinc content. Lots of threads on ZDDP content requirement.
Personally I change the oil often enough that synthetic is just more expensive with little if any value when you consider the extra leaks you will have.
ZDDP is the issue you need to be more concerned about. But if you are going to go Synthetic this was put out in 2012 by Mobil
"For older, flat tappet engines where wear may be more
of a concern, we offer a number of synthetic oils which are higher in
phosphorus than API SN/ILSAC GF-5 oils. These include Mobil 1 15W-50
(1,200 ppm), Mobil 1 0W-40 (1,000 ppm) and Mobil 1 High Mileage 5W-30, 10W-30
and 10W-40 (900 ppm). For all newer engines and flat tappet engines in normal
service, API SN/ISLAC GF-5 oils are preferred for better fuel economy and for
the protection of catalytic systems with lower phosphorous (800 ppm)."
Personally I would not run any oil with less that 1,000 ppm & prefer 1,200 ppm but stay below 1,600 ppm as you are getting in the range that is considered to high and will do damage. I do not like to use additives as I cannot determine what the actual ZDDP ppm is.
And yes I know that GM now says that 800 ppm of ZDDP is good enough with the other oil additives that you have in most modern oils. I also know that the IRS says they are not political because that would be against the law, the Easter bunny is dead, etc.
Corvette is a registered trademark of the General Motors Corporation(GM) &
Chevrolet Motor Division. Vette Registries, LLC is responsible for all site content (except for member submitted content or where otherwise
noted) and does not claim or imply that Chevrolet or
GM is responsible for Official C3 Vette Registry content. Vette Registries, LLC is independent from GM and is not affiliated
with, sponsored or supported by GM. Copyright/trademark/sales mark
infringements are not intended, or implied and are in fact used to support
GM, Chevrolet and Corvette.
Official C3 Vette Registry content is Copyright 2001-2017, Vette Registries, LLC. Content may not be reused without written consent. All Rights Reserved. NS
Corvette (Vette) Model Years on this site: 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982