Additives

[fitz11]

Morning everyone,
1969 Javelin 390 4 speed

What additives should I be running in my engine and my fuel if any?
Engine has no modifications and using premium gas

[Big Bad AMX]

Without any doubt you should be running at least an octane boost. I run Lead Supreme 130 which is both a lead additive and octane booster. It's not easy to find though. Your 390 has a 10.2:1 compression and when new 100 octane MINIMUM was recommended. If you just run premium pump gas without octane boost you run the risk of breaking pistons.


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