1. carrman

    carrman Well-Known Member

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    So, my 451 has been working great. I've run it for almost 2 years, but noticed last summer she likes drinking coolant. Thought maybe head bolts not sealed, then possibly a head gasket. I'll cut to the chase; my Lee Petty built 346 heads have developed a crack on the passenger side head. I need new heads. My dilemma is this, I can get a set of 452's or 346 pretty cheap, and send them to a machine shop for reconditioning. Might be able to reuse my oversize valves but I won't have the port work my Petty heads do. I worry about giving up a lot of the 451 horses my build has. My other choice, I get a set of 440 Source heads. relatively close to the same costs. Anyone have any real world experiences to share here? I'm at a dilemma on how to spend. IMG_7101[1].JPG
     
  2. carrman

    carrman Well-Known Member

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    One other question, angle plug heads will have the plugs interfering with my HP manifolds correct?
     
  3. Ross Wooldridge

    Ross Wooldridge Senior Member FCBO Gold Member

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    The angle plug heads will interfere with your HP manifolds. Can the heads not be repaired?
     
  4. Davea Lux

    Davea Lux Senior Member FCBO Gold Member

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    Assuming that the head does not have any internal leaks into the combustion area, you can probably pull the head and have it welded, an inspection will need to be done to see if that is possible with the head off the car. They heat the head up nearly red hot and weld a bead over the external crack, depending on where the crack goes they may machine a grove into the head before welding it.. They then cool the head slowly so that it does not warp. The valve guides if you the bronze one's installed may need to be replaced and all of the valve gear needs to be removed from the head prior to doing any work on it. This is all fairly expensive and you will still have a head that has already failed once, and might crack again along the weak spot where if failed before, so it may be time to consider replacing the heads as a pair. From the photos supplied, your head may have cracked between the water jacket and the exhaust port, mopar heads sometimes did that if too much metal was removed during the porting process.. It will not usually be repairable if that is the case. I would suggest a hydrocarbon test on the coolant, that will tell you if exhaust is getting into the cooling system.

    Dave
     
    Last edited: Mar 5, 2019
  5. carrman

    carrman Well-Known Member

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    Thinking Lee got a little aggressive with his metal removal big_valves.jpg Img_3423.jpg
     
  6. Davea Lux

    Davea Lux Senior Member FCBO Gold Member

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    Those heads were pushed to the limit, you will be able to tell a lot more about the type of failure you are dealing with via the hydrocarbon test and a visual inspection with the head removed.

    Dave
     
  7. bajajoaquin

    bajajoaquin Senior Member FCBO Gold Member

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    440-Source heads are not angle plugs.
     
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  8. carrman

    carrman Well-Known Member

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    When she warms up, the crack begins to leak, and the exhaust changes color.
     
  9. carrman

    carrman Well-Known Member

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    That's how I'm leaning since I don't want to run headers.
     
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  10. Davea Lux

    Davea Lux Senior Member FCBO Gold Member

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    If you can smell antifreeze from your exhaust, you know where you are.

    Dave
     
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  11. thrashingcows

    thrashingcows Senior Member

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    I would choose the 440-source heads as well, may as well get as much performance out of the head as possible, rather then corking your motor with stockish 346/452 heads.
     
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  12. carrman

    carrman Well-Known Member

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    It never smelled before, but now we had tried new head gaskets, and actually sealing the head bolt threads(Thank you Bullet Machine) we're getting a bit out of the exhaust.
     
  13. carrman

    carrman Well-Known Member

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    Yeah, this was a huge concern of mine also.
     
  14. 73Coupe

    73Coupe Well-Known Member

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    Agreed. We're making sausage until the head is pulled and inspected. Might as well pull and inspect the other one while you're that deep. Were the heads magnafluxed?
     
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  15. carrman

    carrman Well-Known Member

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    We found the crack today, there's no doubt about it.
     
  16. CBODY67

    CBODY67 Senior Member

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    Noting how close the edge of those valves are to the edge of the combustion chamber, those larger valves might be shrouded enough that they aren't flowing much better than 2.08/1.74, in reality. Everybody was recommending those sizes well before and flow bench tests were every done, I believe. Better to increase port flow in the ports than just via huge valves that are shrouded.

    452s worked with the Mopar Perf porting templates are supposed to flow as well as the prior 906s did with the same work done to them. But the 452s might need more surfacing to get the chamber volume down to what the 906s started with?

    440 Source or Indy?

    CBODY67
     
  17. carrman

    carrman Well-Known Member

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    440 Source.
     
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  18. Shamu70

    Shamu70 Member

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    No one speaks of the Edelbrocks anymore;
    is it just a cost thing?
     
  19. carrman

    carrman Well-Known Member

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    Edelbrocks are angle plug heads. Can't run them with the HP manifolds.
     
  20. Shamu70

    Shamu70 Member

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    440 Source can have HP manifolds attached? I know it was said above, but gotta be sure.
    And would a Stage 6 head maybe be a good alternative?