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flathead head question

Discussion in 'The Hokey Ass Message Board' started by a-boy-named-sue, Jan 18, 2009.

  1. a-boy-named-sue
    Joined: Jan 18, 2006
    Posts: 45


    Are all aftermarket 24 stud heads interchangable? Other then the stud count and inlet what is the difference between heads? I'm looking to eventually rebuild my 8ba and have these offy heads(see pics). Are they usuable on my 8ba block?Thanks guys.

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  2. Yes, but you will need to block off an exposed water gallery in the block at the front.
  3. a-boy-named-sue
    Joined: Jan 18, 2006
    Posts: 45


    only on the passenger side right? what is the best method of doing this?Thanks HF
  4. no worries, i dont know the best way to do it, but someone will know. I need to do it on my next build so I want to know as well.
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  5. pasadenahotrod
    Joined: Feb 13, 2007
    Posts: 11,776

    from Texas

    The only difference in old style and new manufacture heads is that all the new heads require and use only 1 length of head stud and the heads are therefore flat across the top rather than having indents around many bolt locations as are stock heads. This new design has increased the cooling water jacket capacity of the heads.

    Old style or I guess we could say original speed heads have the indents around various bolt locations so the heads can be installed directly in place of the original iron original heads without modification.

    The 24 stud 38-48 heads can be installed on the 49-53 blocks and this was very commonly done in the 50s-60s until now.
    Last edited: Jan 18, 2009
  6. a-boy-named-sue
    Joined: Jan 18, 2006
    Posts: 45


    thats great thanks guy...does anyone have any idea for block off methods?
  7. Tap the hole in the block with an NPT tap. Sink the tap deep enough so that a socket head pipe plug will be slightly recessed when installed. Use plenty of sealer when you put it in.
  8. J'st Wandering
    Joined: Jan 28, 2004
    Posts: 1,668

    J'st Wandering

    Rig up something like this to clamp the distributor. This is for a chevy distributor so depending on what you have but you get the idea. Saves the $150.


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  9. 31ACoupe
    Joined: Nov 14, 2005
    Posts: 1,416


    For the plug I just used a wooden dowel cut to fit and hammered it in. Use the early gasket too and when you place it on the deck you will see what needs plugging. For the distributor you can just drill the boss and use a screw to hold it in place or make the hold down which is easy if you have the equip. The early heads look better too, IMHO.
  10. Ole don
    Joined: Dec 16, 2005
    Posts: 2,915

    Ole don

    I used new Offy heads on my 8BA. I had to plug the front hole in both heads, and the small hole in the block. Just use a 1/4 pipe tap and a flush plug. For a dizzy hold down I sawed a slot in the front cover and used a screw type hose clamp. It works fine. I used all factory long head bolts at 55 Ft. lbs.
  11. The heads in the pictures have been milled quite a few times -- notice how small the piston dome areas are. You may not have enough piston-to-head clearance. They may need to be redomed - which is somewhat expensive. Make sure you check your piston to head clearance. If you need to have them redomed, you could call H&H Flatheads in the SoCal area.
  12. Capitan Insano
    Joined: Apr 29, 2007
    Posts: 289

    Capitan Insano

    Those heads need work. Resurfacing, doming and welding around some of the water holes would not hurt. When you have offy heads like that it is almost better to go with new ones. If it was something rare I would put the money into it. Thanks again for the H&H mention.
  13. blown49
    Joined: Jul 25, 2004
    Posts: 2,213

    Member Emeritus

    Also notice that they are 400 heads for .400 cam lift maximum. If you're also considering a cam change they may have to also be re-worked in valve pockets.
  14. Is this Mike from H&H? If so, it was a pleasure meeting you at the Goodguys show - I was the guy that talked about blown flatheads quite a bit and managed to convince you that you needed to sell the 4-pot 4-71 manifold prototype :D I'll be giving you a call about blower drive stuff . . . just need to finish some other stuff first.

    I agree that to invest hundreds of dollars in an old set of Offy heads doesn't make a whole lot of sense to me -- there is nothing rare or unique about them. If they were mine, I'd consider selling them for a couple hundred and then saving for a new set. Just one man's opinion . . .

    Dale 'Bored&Stroked' Hays
  15. gashog
    Joined: Dec 9, 2005
    Posts: 978


    There are two schools of thought on headgaskets. Some folks feel the later gaskets on 59A's with stock heads to improve cooling and feel they should also be used when running early heads on an 8BA. I am running a set of vintage Edelbrock high compression center dump heads on my 8BA and have no cooling problems with the 8BA gaskets.

    With all the core shift problems I have heard of with new heads, you may have to do as much machine work as you would on your old ones til you're done. Ol Ron may be able to help you out with the redoming. If you have erosion problems in the water ports, you can tap for 3/8" aluminum plugs and redrill the ports to restore the original size.

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    Last edited: Jan 19, 2009

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