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Anyone have knowledge of Model T performance heads?

Discussion in 'The Hokey Ass Message Board' started by xrw urabus, Apr 28, 2011.

  1. xrw urabus
    Joined: May 26, 2010
    Posts: 49

    xrw urabus
    Member
    from ohio

    Hello,

    I am rebuilding a 1926 Model T and am at a point where I need to have the original head machined or purchase an aluminum performance one. Does anyone know the advangate or disadvantage of decking the original vs purchasing an aluminum performance head of some type?

    <O:p</O:p

    Thanks,
    Jim<O:p</O:p
     
  2. Tim Rocheford
    Joined: Oct 24, 2007
    Posts: 28

    Tim Rocheford
    Member

    There are high performance T heads available. They have better designed combustion chambers than the stock heads and most take modern spark plugs. They aren't cheap though. I got my stock head shaved for about $60.00.

    I shaved 1/8" off the head and run modern plugs in adapters. It goes like a raped ape. If you shave the head, you do need to be careful. You'll need a head with a good, thick deck and the head bolts will need to be ground down a touch so they don't bottom out in the holes.
     
  3. slodat
    Joined: Aug 18, 2009
    Posts: 189

    slodat
    ALLIANCE MEMBER

    Stock Model T's had two different heads. A "low" head and "high" head. The high head was created due to poor quality gas.

    The advantage of the after market heads is the redesigned combustion chambers.

    Here are some photos of the different heads as well as some tests. Check out all the links. Great site to check out:
    http://clubs.hemmings.com/clubsites/MTFCTulsa/Tech/head_photos.htm
     
  4. MrModelT
    Joined: Nov 11, 2008
    Posts: 2,657

    MrModelT
    Member

    Early stock T heads (pre-1916) have a compression ratio of 4.16:1 and the late heads (1916-1927) are 3.98:1.

    The aluminum "Z" heads are 6:1 compression and add 7 to 10 hp. They run about $360.00 and are nice because they are simple and bolt on. I have one on my Roadster and I could feel a noticeable difference in performance.

    You can shave the stock heads, but I think you would need to take off quite a bit to get the compression that high, but it all depends on what your goal is.
     
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  5. You should try posting your question on the Model T forum of fordbarn.com. I think there is also a public forum at MTFCA.com but may be wrong.

    Charlie Stephens
     
  6. shooter54
    Joined: Apr 25, 2006
    Posts: 5,145

    shooter54
    Member

    What fer? We got MrModelT right here.;)
     
  7. MrModelT
    Joined: Nov 11, 2008
    Posts: 2,657

    MrModelT
    Member


    lol! :rolleyes:

    I like the Z-heads because of the 6:1 comp ratio and the fact that they are bolt on. If you building a fairly "hot" flathead T motor, you'll want the 6:1 compression ratio, along with a decent cam (.280 or .300 grind) and larger valves (283 Chev are a good substitute). This, and having it ported/relieved will allow you to run a variety of 30's or 40's vintage 1 and 2 - barrel carbs with ease..... giving that T mill plenty of snap and a whole lot of spunk.

    A friend and I built a T speedster that runs a .300 race cam, 283 valves, .020 aluminum pistons, 6:1 Z-head backed up by a Warford O.D. and stock 3.63 gears in the rear axle. We installed a 2 - barrel Holly Model 94 with .060 jets that it runs exceedingly well with.....actually a "scalded rabbit" is more of an appropriate term :D

    The new engine for my T will be built much the same way, but run larger pistons, be ported/relieved.....and run a Burns intake with twin "97's" :D
     
  8. GMC BUBBA
    Joined: Jun 15, 2006
    Posts: 3,363

    GMC BUBBA
    Member

    Make that two votes for the "Z" head i have two Ts and run the z on both of them , best head for your money. Adds some power for sure........:D
     
  9. xrw urabus
    Joined: May 26, 2010
    Posts: 49

    xrw urabus
    Member
    from ohio

    Hey Everyone,

    Thanks for all the information. It seems we will be saving up for the Z-head. My thought is that it will cost $60 - $100 for the machine work so we only have to save the extra $300 or so. Thanks again for your input.

    Jim
     
  10. I'm going to throw my .02$ in here...I do like the "Z" head, it adds power, utilizes the superior 'Ricardo' style chamber, and looks like a stock head. Not sure exactly where we're getting the 6:1 compression ratio figure, the Tulsa club calculated theirs at 5.3:1. Still, you're looking at up to a 35-40% increase in power just from bolting one on.

    The only problem I have with the Z head is that I've heard of a few of them that had casting flaws causing the water neck to be out of line. I have also seen one that appeared to have a welded up combustion chamber. I'm sure the vendor(s) who sold these pieces did right and exchanged them, but its something to be aware of.

    The only thing I personally don't care for is the fact that a Z head is not period. Yeah it looks like a high head, but the high heads (even milled down) were hardly a hop-up item. If you're looking for period performance (20's that is) look for a low head and mill it 1/8 or 5/32". Green heads were available as early as 1918, and the Waukesha-Ricardo came on the scene in 1923. The Giant/Haibe/Super Power heads were introduced around 1925 IIRC.

    If you have deep pockets, go for an Akron, Frontenac, Rajo, or Laurel-Roof OHV.
     
  11. MrModelT
    Joined: Nov 11, 2008
    Posts: 2,657

    MrModelT
    Member

    I have never heard of anything other than 6:1, but never tested one myself. I also never heard of the "Z's" having issues....the early "z" head castings maybe? Mine was a really nice casting.....bolted up perfect.

    I will agree that the Z-heads are not very period looking. The Ricardo, Sherman and Super Power heads are rare and getting hard to find these days...heck, the last Ricardo I saw (and the Sherman next to it) had an $950.00 price tag :eek:

    For that reason, the Z-head is certainly a cheap, easy and plentiful substitute.

    ...Now if I had the cash, I would have a ROOF Model C, RAJO BBR, Fronty or maybe a Gallivon DOHC head sitting on my T block right now :D
     
  12. Here's a photo of a jacked up Z combustion chamber...the owner claims it was purchased "recently"; [​IMG]

    No doubt this is probably an odd-ball - just something to make sure and check out. There are two folks that posted on this thread on the MTFCA who mentioned the water neck flaw...again probably 1 in 10,000.

    I can't vouch for the accuracy of their measurements, but the math is right...the Tulsa club website shows 5.3:1 CR (5.25:1 compression using the formula given on their head page).

    Nonetheless it's a wonderful product and thousands swear by them.
     
  13. MrModelT
    Joined: Nov 11, 2008
    Posts: 2,657

    MrModelT
    Member

    That is a bit "weird" looking....damage to the pattern maybe? I know mine doesn't look like that.

    I would have to do the calcs myself, but 5.25:1 just seems low to me....doesn't sound right, but it's probably just me :D
     
  14. xrw urabus
    Joined: May 26, 2010
    Posts: 49

    xrw urabus
    Member
    from ohio

    I have posted this same question on the Model T forums and am getting loads of information.

    Thank you to everyone who has replied. I appreciate the input, it will assist me in making an informed decision.

    So the new Z-head will be in the $350 range. It may delay the project a month or so but will be worth it in the end. We just purchased all the bearings, bushings and bands to rebuild the transmission, front and rear ends. Also new pistons, valves, seals, machining of the block and regrind on the cam all in the last few weeks. So I need to hold off on the spending for a short while. If not my wife may notice how much is being put into the car :rolleyes:.

    Thanks again,
    Jim
     
  15. Best of luck Jim! Keep us posted on your progress!
     
  16. bobbyb
    Joined: Jun 28, 2009
    Posts: 151

    bobbyb
    Member
    from ohio

    Try contacting Snyder Antique Auto Parts in New Springfield Ohio. Try web site for phone number. They specialize in 'T' & 'A' parts.
     
  17. Grahamsc
    Joined: May 13, 2014
    Posts: 466

    Grahamsc
    Member
    from Colorado

    Performance t out of texas makes a high comp head that from appearance has a smaller chamber than the z heads I see pics of on here.
    It runs very well on my t
     

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