I have a 1959 327/350hp 4 speed and not sure correct additives needed with unleaded gas. Can anyone advise correctly as it seems everyone has their own ideas

Asked by May 16, 2014 at 12:26 PM about the 1959 Chevrolet Corvette Convertible Roadster

Question type: Maintenance & Repair

I am trying to find out specifically what is the correct additives for a 1959 corvette
327/350hp so when I fill up with unleaded I have no issues.

2 Answers


The classic cars guy out here all use sta-bil marine, the add in a lead substitute if their engines haven't been modified for unleaded fuel. If it is a 350 horse engine then you really need high test fuel, you still might have to add some octane booster to keep it from pinging.


Since it is not the original engine, it might have hardened valve seats and not need any lead substitutes. It also might have reasonably low compression and not need high octane fuel. I run regular unleaded fuel in my Vette with no trouble at all.

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