69 Heads.... Replace/rebuild?

Discussion in '1965 - 1973 Classic Mustangs -General/Talk-' started by Andrew Toolen, Nov 3, 2013.

  1. Need some help....
    I have a stock 69 Grande and am about to do some upgrades!
    Motor is all stock except for the heads that were put on before I bought it.... It had stock 2V heads, and they put on 4V heads.... Still technically needs lead additive, I havent used it..... Ive had her for about a year now and ready to do some work!
    Have a Holley 600, Edlebrock Intake, and since I am doing that I figured its time for new heads and cam....

    Not sure what heads are on there now... Only marks when I take the covers off are in the pic, anyone know what heads they are?
    Are they better than the Gt-40 heads...


    Attached Files:

  2. is this a windsor or cleveland engine? if a windsor there is no such thing as a specific 4v head, like there is with the cleveland. also the heads you have in the picture are a D8 head meaning it was a part released for production in 1978, which means they are set up with hardened valve seats for unleaded fuel. by the way, since it is a D8 head its not a cleveland head.

    now if the heads are in good shape, then run then, unless you want better performance, in which case you want a better head. the GT40 heads are good, but there are better heads on the aftermarket depending on what you want this motor to do.
  3. Oh ya she runs great, just want to wake her up a bit... I think that will happen with the headers, and going from a 2 barrel carb and intake to a 4 barrel carb and intake!
    78.... Kid told me he put 70 heads on.... Better or worse? Not wanting to go wild with the motor, just want to make sure I dont want to redo things next year....
  4. the only real difference between the 70 and the 78 head is going to be the combustion chamber size, the 78 head i believe is 64cc while the 70 head is closer to 54cc, which means a big gain in compression ratio with the smaller chamber, going from about 8:1 to around 10:1 roughly.
  5. SO you think I should put a set of GT-40 heads on?
  6. the GT40 heads are good ones to use for a budget build. just remember that there are GT40 and GT40p heads. avoid the P heads as they have a revised plug location that requires different headers. you can tell because the plugs are not angled like the regular heads are.
  7. Thanks for the help!!
  8. anytime