Question 1: What is the recommended oil to use for a 1964 394 cubic inch Starfire engine? I am particularly interested in knowing if I should use an oil with a zinc additive?


Question 2: Should I put a lead additive in the gasoline? I've been adding Marvel Mystery oil to the gasoline and occasionally I put in a lead additive, but I really don't know what is the proper thing to do.


Thanks in advance for your help!

 

You will get a lot of answers. I prefer a 15/40 oil for high mileage engines. Quaker State Defy supposedly has a high zinc, as do other high mileage oils.
Engines that have mileage on them will do fine for normal use with no-lead fuel. Just use enough octane for your compression.
JMHO

 

This is exactly what I do. I have a '67 Delta 88 with the 425, high-compression, and I've just run premium unleaded straight from the pump with no additives since I bought the car in 2009, and it has always run fine. The engine now has 131,000 miles on it. I would not bother adding any lead additives, but as Patrick notes, be sure to use the correct octane.

As far as oil, I don't bother looking for oils with the zinc additive (ZDDP). I just use whatever 10W40 is on sale at the local auto parts store and add a container of STP oil treatment each time I change it. The STP has the needed zinc.

 

Thanks so much for your reply. I appreciate the effort you took to share this info with me!

 

Thanks for the info!! I'll start using the STP. Sounds like good stuff. The time and effort you took to reply to my question is very much appreciated!!!

 

The 1964 Oldsmobile Service Manual, page 2-1, recommends 10W30 above freezing:



Any good quality oil in the 10W30-15W40 range should be fine.

I would avoid using synthetic oil in an old engine, as it can sometimes umask leaks you never knew you had.

A zinc additive is a good idea.
As Jaunty said, STP should work fine.

I prefer to use Lucas Break-In Additive, which has a metric s__t-ton of ZDDP -
I use about an ounce per oil change, and one bottle lasts me a long time, for about the same price of the single-use bottle of STP, but it's all good either way.



A lead additive is not strictly necessary, but with the high compression of the Starfire engine, I would definitely be using an octane additive, or running with the timing VERY retarded.

Coincidentally, the best octane additive is probably Octane Supreme, which is tetraethyl lead.
You want to boot it to an AKI octane of about 98 (that's 5 points about pump 93).


Good luck!

- Eric

 

Thank you very much for this information!


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Hi Bill - I accidentally hit the "Submit" button too soon - go back and check my completed post.

- Eric

 

Thanks again Eric!