Magnum Heads onto LA block

Engine Swaps

  1. Bruceynz

    Bruceynz Well-Known Member

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    Hi Guys,

    I thought I saw a sticky for this somewhere, a search didn't turn up anything, so if there is a post can someone point me in the right direction.

    I am not happy with the performance of my 360 LA engine, it goes ok! But it should go better! I suffer from all the same problems, low comp, open chamber heads, poor flow. I have been exploring all kinds of options (5.7 hemi, 408 crate engine, alloy heads) but I think what I want to do is put magnum heads onto my LA block.

    So I am going to need

    Heads - What are good bang for buck magnum heads? (I see recondition ones on ebay for the $200 mark) does anyone have any good heads? Can anyone recommend any that might be a bit better than stock?

    Push rods - What length can anyone recommend some? (I need some with holes up the middle)

    Rockers, where do I get all the rocker gear I need?

    Valve covers, should be able to find them on ebay, need low profile ones to clear my brake booster.

    And I will need an intake, but thats not to bad to sort, edelbrock will have that covered.

    Thanks
    Bruce
     
  2. brotherGood

    brotherGood Well-Known Member

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  3. kkritsilas

    kkritsilas Well-Known Member

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    Bruceynz:

    Start here:

    magnumswap.com

    For a good background on the Magnum/LA differences.

    A lot of background material is in this article (based on the 318, but covers a lot that applies to the 360):

    318 Engine Build - A Parts Book 400HP 318 - Mopar Muscle Magazine

    Some ideas are here:

    350-400hp budget build 360 ideas???

    If you are going to d a full build up, I would skip the shaving of the decks, just go with the EngineQuest or Magnum heads, and the KB pistons and thin head gaskets that increase compression. Compression is nice, but it has to run on regular gas, which around here mean 89 octane. I know you will be giving up some horsepower, but I don't think it is worth chasing every last horse available if it means that you need to run mid grade or premium gas. If you have the money and do want it, go for it, but know what you are getting into.

    Also, the Magnum heads have a known tendency to crack between the valves. Have any Magnum heads that you want to use thoroughly checked out. Part of the reason that the EngineQuest heads exist is because of this problem (they are also avallable with LA pattern intake maniforld bolts, so your current intake will bolt up).
     
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  4. Greg55_99

    Greg55_99 Well-Known Member

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    I've heard the same about Magnum heads tendency to crack. Kinda puts a damper on boneyard parts.
     
  5. kkritsilas

    kkritsilas Well-Known Member

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    The only real bad point of the Magnum head is the cracking. In almost all other ways, it is a really good factory head by any measure. Ma Mopar did a great job of correcting a lot of the flow restrictions in the LA heads, decreased the combustion chamber volume, and upped the valve size. Seems like they designed the area between the valves a little too thin.

    I have seen one set of cracked Magnum heads. Had to look real close to see it (it had to be pointed out to me). Some are saying that some cracks are not fatal, but all Magnum heads need to be checked to find out if they are leaking coolant in my mind, just to avoid having to tear down an engine a second time. The EngineQuest heads are specifically designed to avoid this type of cracking. In addition, they actually flow better than the Magnum heads do. Not a night and day difference, but the improvement is there. With the other advantages brought by the EngineQuest heads (crack elimination, ability to order them with LA intake manifold bolt pattern), they are an option that should be considered seriously.
     
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  6. 89.Fifth

    89.Fifth Well-Known Member

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    It's a LOT easier if you start with a Roller Cam block (85-91)
     
  7. hemijoe

    hemijoe Well-Known Member

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    stay away from magnum parts they are prone to cracing use an early set of 318 heads to get compression up to 11 to 1
     
  8. brotherGood

    brotherGood Well-Known Member

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    My magnum parts are fine...I can get another set that have been checked for cracks and are good to go for 150 right now. the exhaust seats are vulnerable, but that's usually related to overheating from what I've heard. once you find a good set, they're well worth it