bought a 70 lemans sport with the 350, I had a 69 firebird as a kid with the 350 had a cam ,intake like most kids and I ran 10w30 , my cousin had a GTO he drag raced and ran strait 30w in it, car I bought he gave me a slip saying that mech put in 20w50 saying only run that. I think its a little much 10w40 is what I would run but since he's been running that just wondering if I should stay with it, what's your thoughts on it?
oil weight question
- Thread starter hdbob5454
- Start date
Classics Fan
Member
20w50 is a bit heavy in my opinion. Depending on your climate I’d go with 5w30 or 10w30. I live in the Pacifice Northwest and run 10w30in all my 60’s and 70’s motors. If your engine is stock with flat tappet lifters be sure to use either a high-zinc motor oil like Valvoline ZR-1 or use an additive like Rislone ZDDP.
