64 300 spark plugs?

Discussion in 'Small Block Tech' started by MnBuick64, Sep 29, 2017.

  1. MnBuick64

    MnBuick64 Member

    Hi Guys,

    Haven't jumped on here in quite a while due to life and everything getting in the way.

    Question for everyone is about spark plugs for 1964 Lesabre 2dr with the 300. Aluminum heads

    I am using some ACDelco 44ffs plugs in it. My 64 Buick chassis manual says to use the 44ffs plugs, it also says that if you are doing a lot of highway driving to use 42ff plugs.

    I had no trouble finding new old stock 44ffs plugs, I have 2 sets for backups. I cannot find a 42ff plug anywhere. I guess I don't need (new) old ones but is there something that matches the 42ff plugs out there.

    We do almost exclusively highway driving to car shows so I am wondering if I should be running the 42ff plugs.
    The engine does run on after the the key is turned off, wondering if it has to do with the plugs and highway driving.

    Also, do you think there was a typo in the chassis manual and it should have stated 42ffs? not 42ff.

    Thanks to anyone who reads this or chimes in.

    Have a good one. Fun car season is almost done for me here in Mn.
     
  2. TrunkMonkey

    TrunkMonkey Well-Known Member

  3. DEADMANSCURVE

    DEADMANSCURVE my first word : truck

    at work , curious . so looked 'em up - '64 'sabre 300 - R44F comes up . easy enough to get . 43's or 42's would be cooler .
    tried to supercede your 42ffs number - bunch of dif plugs came up . but i would dbl check any superceded numbers . on anything actually .
    had a 64 300 alum head lesabre a long time ago but i can't remember the plug # .
     
  4. MnBuick64

    MnBuick64 Member


    Would the R42f or R43f work on the aluminum head version?
    When comparing the 44ffs and the R42f it looks as though the 44ffs is a bit longer, somewhere I read that the alum. head 300's needed the plug in further than the cast iron ones.
    Looks like there is a one or two thread difference between the 2.

    The guy I bought car from had 3 R42's and 5 R43's in it. I switched to the 44ffs that the manual called for.

    With today's fuels would it help or hurt to run a cooler plug. Again I do 96 percent hwy driving.
     
  5. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    The best plug for any car is the coolest plug that won't foul.
     
  6. DEADMANSCURVE

    DEADMANSCURVE my first word : truck

    hmmmm , computer at work never asked about alum ? and I took it for granted all lesabre 300's in 64 had those heads . worth checking . i'll cross check against an old AC catalog I have .
     
  7. philbquick

    philbquick Founders Club Member

    The aluminum heads take a longer thread so they don't strip.
     
  8. DEADMANSCURVE

    DEADMANSCURVE my first word : truck

    found it . '93 AC plug catalog . some info :
    for 64 300 it sez #44FFS ( same listed for the 62-63 215 ) . it looks like it lists an alternate plug #R43fs . if that looks the same it should be a step colder and resistor . autolite book lists a #275 and it does look like longer threads . so a #274 would be a colder plug .
    R = resistor
    F = 1/2" ( 12.7 mm ) reach
    FF = 1/2" ( 12.7 mm ) reach , fully threaded
    S = extended tip
    or
    S = 7/8" ( 22.3 mm ) moderate long reach 23/32" ( 18.25 mm )
     

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