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Aluminum Heads Vs. Cast Iron HEads?

Discussion in 'The Garage' started by OffRoader93, Jan 29, 2004.

  1. OffRoader93

    OffRoader93 1/2 ton status

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    Will going from iron heads to aluminum heads (both heads the same exacts specs)give you any more power? Thanks.
     
  2. Z3PR

    Z3PR Banned

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    I don't see how if [ QUOTE ]
    (both heads the same exacts specs)

    [/ QUOTE ]
     
  3. Muddytazz

    Muddytazz 1 ton status

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    If they are the same exact spec, no different in HP....only thing that i think could be different is that one runs a little bit hotter than the other.
     
  4. Sandman

    Sandman 3/4 ton status Author

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    you'll lose some weight. That is always nice.
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    Exact same specs, aluminum heads will lose power. (they shed heat faster, which affects combustion)

    Of course, when talking about non-similar heads, you can run more compression on the aluminum heads (again because of heat dissipation) but the last article I read on this very situation, was that the difference made up in the CR increase would equal that lost from the different material. So net gain either way? 0. /forums/images/graemlins/smile.gif

    You do lose front end weight though, which is probably a non-issue in these trucks. Sure, the weight is probably 80/20 bias to the front, but thats what, 4000lbs on a 5000lb rig? Even a 200lb difference in weight won't matter. The loss in weight will help acceleration and in town mileage, but again, even 200lbs is not much on a 5000lb rig, and not what you lose with aluminum heads.

    AL L98's are good heads for instance, but other than getting your hands on a cheap pair of AL heads, cast iron makes more sense for a non-race heavy vehicle where weight isn't nearly as important.
     
  6. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    I'm with Dorian...Aftermarket heads are a lot better because they allow you to run more compression on the same octane gas. Some aftermarket alum. are better than others but If you have a big inch small block than it makes a world of a difference. For example...AFR told me that with their 195cc 2.02 heads, I would gain around 50HP over my stock iron GM heads on my built 406. There is a bigger difference when you have more cubes and/or more motor mods than with a milder smaller motor. If you plan on a built 383 or 400 than aftermarket heads are THE WAY TO GO because the stockers just plain don't flow enough air in the upper RPMS for a big motor. Even a built 350 can run out of air with stock heads. THe only factory heads worth running are the late model vortec heads or some classic fuelie 2.02 heads. I am going to buy a set of AFR's as soon as I can! Don't make the same mistake I did, choose a good head. /forums/images/graemlins/thumb.gif
     
  7. k20

    k20 3/4 ton status

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    I concur, they are going to seem the same as aluminum will lose power because of shed heat, but seem faster because of weight saving. It would seem to be equal in performance.
     
  8. Triaged

    Triaged 1/2 ton status

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    [ QUOTE ]
    Exact same specs, aluminum heads will lose power. (they shed heat faster, which affects combustion)

    Of course, when talking about non-similar heads, you can run more compression on the aluminum heads (again because of heat dissipation) but the last article I read on this very situation, was that the difference made up in the CR increase would equal that lost from the different material. So net gain either way? 0. /forums/images/graemlins/smile.gif


    [/ QUOTE ]

    Exactly!
    That is why I like to say you "have to" run more compression insted of you "get to".

    Where you will really notice the difference is going from stock heads to aftermarket aluminum. They make more power because they flow more...and the weight doesn't hurt either.
     

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