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Need Flathead Advice

Discussion in 'The Hokey Ass Message Board' started by GreenMonster48, Aug 1, 2012.

  1. Just got good news that the flathead block I bought last year checked out OK after a hot tank and mag.

    It's for my old truck and I don't want to build a nasty street machine or anything. Stock stroke, 3/4 cam, 4 barrel intake and Edelbrock heads and probably a hotter ignition.

    My plan is to get the surfaces cleaned up, bored out to the next higher number (.010, 020, 030), and new cam bearings installed. I was then going to bring the block back home and install one of H&H's stock 3 3/4 crank kits myself. Does this sound reasonable? The machine shop warned me that sometimes the aftermarket pistons/rings can be off by a few thousanths. Is it worth just having them do the install, or is this something I can do myself?
  2. The machine shop may also be trying to get a few more bucks out of you too.

    If you have accurate tools; caliper, micrometer, bore gauges, torque wrench etc. and trust yourself reading the measurements...then go for it.

    There's bunches of books out there that detail flathead rebuilds. Also, maybe find a rodder in your area that knows flatheads and can look over your shoulder while you go over it.

    Plus there's this HAMB place that has lots of knowledgeable folks.

    Take your time and be sure of your work. Invaluable experience.
    Last edited: Aug 1, 2012
  3. Rickybop
    Joined: May 23, 2008
    Posts: 6,573

    from Michigan

    Heck yeah, you can do it. Do some studying, and start a build thread, and ask for advice as you go...every step of the way. And if pistons are "a few thousandths off", then ya send 'em back.

    Even if I was a beginner, I think I'd rather slowly and meticulously assemble my own engine, having advice and encouragement every step of the way from multiple Hambers. That way, you learn a lot, have some fun, gain some pride and bragging rights, and you know absolutely for sure that the builder (you) paid attention to every detail...'cause you care. As opposed to a "pro", that really doesn't give a crap. Also, we get to watch, and maybe even learn something ourselves.
  4. Andy
    Joined: Nov 17, 2002
    Posts: 4,608


    The valves are the biggest pain in the a$$. I would drill the block for the punch to hold the lifter from turning and then use the hollow adj lifters. The main oil galley plugs are special so don't loose them. The fuel pump bushing blocks rodding out the galley. It can be driven down into the cam bearing hole but takes a dedicated driver.

  5. afaulk
    Joined: Jul 20, 2011
    Posts: 1,189


    Quality modern day pistons are truly a marvel of machining technology. If your over bore is done to spec. +.010 or whatever, pistons made to fit that bore size will fit. Gone are the days of needing to fit each piston to its bore. The same is true for bearing/journal sizes. The only caveat is that the machine shop must be able to do precision work. I always check behind them just to be sure nothing was over looked. If you're careful and take your time 98% of engine problems are avoided. That makes the project much more satisfying, IMO.
  6. Goodlife
    Joined: Apr 12, 2010
    Posts: 181


    I have had a couple flatheads and I am now having one built by a top notch shop out of state. For me, I had to recognize the limits of my ability, tools available and how much help I could depend on before I got too involved in an engine build. I came to the conclusion that it would be better to have a professional who knows what they are doing given the fact that the block proved to be good after the mag check and I didn't want to take a chance of doing something wrong.
    The machine shop may be giving you some some good advice from their professional experience.
  7. Russco
    Joined: Nov 27, 2005
    Posts: 4,132

    from Central IL

    I just built one myself, they dont really get any easier than a flathead. I think the machine shop is trying to snooker you into having them do an easy build. If they do the machine work correctly, it goes together for you just the same as it goes together for them.
  8. 40FordGuy
    Joined: Mar 24, 2008
    Posts: 2,907


    Machine shop....Before the block is bored, take your new pistons along with the block..... A good shop will ask you for them, in order to get the correct fit. And that doesn't add to the cost.
    Ask around, re; machine shops,....I like to ask the antique car peeps who they use,...Those are folks super-fussy, about who touches their baby.

  9. Atwater Mike
    Joined: May 31, 2002
    Posts: 10,223

    Atwater Mike

    IF YOU want flathead advice, read this post! ^^^^^ Absolutely take your pistons with you to the machine shop. (they are not all the same size...ever.)
  10. Babar40
    Joined: Dec 4, 2009
    Posts: 313

    from Florida

    Just what Atwater Mike said.
  11. have the block bored with pistons.they will need them for final hone.Tell them what kind, cast or forged.different expansion rate.

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