I am getting ready to change the oil for the first time on our 1968 firebird, has a re-manufactured 1969 6.6L 400 under the hood. TH400 transmission. I am looking at Jeg's and Summit to buy oil. They are recommending 10W30 Red Line synthetic and a host of other oils that are "racing" oil (i.e. Valvoline Vr1), summit even has a semi-synthetic Penn Grade oil listed. Any suggestions? I do not race. This is a convertible that my wife and I drive whenever the weather permits (no snow or ice, or hopefully rain). I prefer putting in a high quality oil, just was skeptical of putting a synthetic into an older engine.

Thank you in advance for any recommendations.
Jake

Just use good name brand oil and add zinc. I use valvolene high mileage semi synthetic since my motors are old and worn out. And add Camshield zinc additive. Since the motor is fresh I’d just use regular valvolene 10w30 and add zinc. In case you’re not aware they took out the highly effective zinc compounds out of oils due to catalytic converter damage since modern engines all have roller cams. Flat tappet cams need the zinc compounds

Thank you Bob. I keep digging and reading and appreciate your answer. it matches with most other responses in FB forums. But you knew that already! I may go with a Valvoline product with the Zinc already in it, just keeps me from having to add it, unless you see that as not being the same?

Thank you again.