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Effect of non-leaded fuel on 1964 390 engine?

Discussion in '1955 - 1966 Classic Ford Thunderbird' started by amillego, Sep 7, 2017.

  1. Hi. I've just purchased an all-original '64 with a 390 in it. I was wondering if it's going to run OK (once I get it running) on unleaded gas. If not, what will I need to do to make it run correctly?
    1. I use a product made by Gunk on my '63. It a Lead Substitute in a gray bottle. Previous owners used it. You can get it at O'Reilly's and most auto stores (also Amazon). Eventually going to pull the heads and have hardened valves and seats put in. I guess it needs the lubrication or you will burn valves and seats.
    amillego likes this.
  2. Misty...thanks for the information. I'll look for it and try it. Cheers, Gordon
  3. I use a lead substitute additive (Castrol Valvemaster), although I have heard it said that for the 1000 miles a year I drive the T-Bird the engine will easily outlast me without the additive.
    Last edited by a moderator: Sep 7, 2017
    amillego likes this.
  4. I looked at having hardened valve seats installed on my 390, but on looking at the amount of material around the seats the reconditioner was reluctant to proceed. I got a second opinion and they agreed it was risky. I'd be interested in any other views.
    amillego likes this.
  5. tbird

    tbird Super Moderator Staff Member

    amillego likes this.
  6. captrick

    captrick Well-Known Member Lifetime Donor

    I had hardened valve seats put in all my 50's and 60's engines and never had a problem. I am still driving a 1967 427 - 425 hp engine even today. The only thing you want to make sure is that the timing is not to far advanced that the engine pings. On your 390 you don't want anymore timing then 36 degrees at 2500 rpm. It is a good idea to use 92 or better octane because of the higher compression of the older engines. Good Luck Rick
    amillego and biddle like this.

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