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Hot Rods Can you guys take me to early Hemi school?

Discussion in 'The Hokey Ass Message Board' started by Doug520, Feb 28, 2023.

  1. woodsnwater
    Joined: Apr 4, 2016
    Posts: 502

    woodsnwater
    Member
    from North Al.

    That 392 piston tip will save you a $$$$. Here's a few thing to know. When you convert to a spin on filter you do away with the oil bypass valve. These old motors are full of sludge, I'd physically brush out every oil passage hole including the rockers. Don't use valve seals on the exhaust valves. It's dangerous to mill the heads to except taller springs, they are thin in that area. And a Suzuki Samurai alternator fits perfect. hemi5.jpg
     

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    Just Gary likes this.
  2. 51 mercules
    Joined: Nov 29, 2008
    Posts: 4,331

    51 mercules
    Member

    If you're going to rebuild go with the 354. I'm not sure what year the 331 is, but late 54's have a wet intake manifold and would need some modes to run an aftermarket intake.
     
    slayer likes this.
  3. gimpyshotrods
    Joined: May 20, 2009
    Posts: 24,481

    gimpyshotrods
    ALLIANCE MEMBER

    X2 on not messing with valve pockets!

    X2 on these being engines designed to motivate 2-ton cars!

    A Model A would scoot just fine with a sock one with a 2-barrel.

    Anything that you add beyond that is gravy!
     
    caprockfabshop likes this.
  4. Sorry for the error,,,,I thought factory 392 pistons were 9 to 1 compression.
    My fault for not being up on my game on the Chrysler brand .

    If I’m not mistaken,,,,,I think the stock replacement Egge pistons are about 800 bucks .
    Not terribly much less than Ross there .

    Contact Bob at Hot Heads,,,,he can help .

    Tommy
     
  5. Gotgas
    Joined: Jul 22, 2004
    Posts: 7,248

    Gotgas
    Member
    from DFW USA

    They come both ways. The 392 was 9.25:1 for 1957, and 10:1 for 1958, the only difference being a little added dome for '58.
     
  6. deucemac
    Joined: Aug 31, 2008
    Posts: 1,644

    deucemac
    Member

    One other item of note. My block came from a 58 Dodge 2 1/2 ton truck . The rear main cap is configured to use a 392 oil pump from the factory. No adapting a 360 pump or anything. Two other things are also different about the block first is when I converted to a Chevy water pump I had to use the early style adapter from Hot heads because of holes on the front face of the block. The other item has to do with the crankshaft pilot hole. It's larger than passenger cars and will take a different pilot bushing. Also keep in mind that if you use a truck engine, they used a gear drive cam which means that you need to convert to passenger car parts. I found out that the timing set for a 318-360 fits perfectly and is far less expensive than original style sets.
     
  7. gimpyshotrods
    Joined: May 20, 2009
    Posts: 24,481

    gimpyshotrods
    ALLIANCE MEMBER

    That's about what my Ross forged pistons were, before tax, and there is no getting around that.

    Given the choice between a stock 392 piston, which requires hogging out the bores of a 354 past several standard overbores, and getting precisely made custom pistons for just the very next overbore, in the desired compression ratio, for basically the same price (and did I mention forged, too), the choice is clear.

    Once you take a 354 to a 4-inch bore, any future work can make the cylinder walls quite thin.
     
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  8. Gotgas
    Joined: Jul 22, 2004
    Posts: 7,248

    Gotgas
    Member
    from DFW USA

    Well, maybe. Parts are getting scarce and labor is way up. Sometimes you assume an old part is usable/good, only to find out it's not (cracked head, gouged crank, etc.). Then there are those insidious costs that you don't think about much, but they add up. Things like transmission (adapter, flexplate, converter, shifter may all need to be addressed), starter, water pump, induction, ignition, cooling, exhaust, charging, brackets, mounts, etc. There may even be brake, steering, or body and floor changes required because it's a hot rod and you just never know how it's all going to fit together.

    I'm not disagreeing with you that it can possibly be done cheaper. I'm just expanding on why I think $20k is in the ballpark of what it will actually cost to get it done.
     
  9. gimpyshotrods
    Joined: May 20, 2009
    Posts: 24,481

    gimpyshotrods
    ALLIANCE MEMBER

    Melling has the 392 oil pump. I think the part number is M-50.

    He's got an automatic, and the adapter to a GM transmission has a pilot adapter for the converter pilot, so good call pointing that out. It might be an issue fitting the adapter, but I am not sure.

    It is worth checking with the supplier to make sure.
     
    Desoto291Hemi likes this.
  10. gimpyshotrods
    Joined: May 20, 2009
    Posts: 24,481

    gimpyshotrods
    ALLIANCE MEMBER

    On the topic of cranks. These are made of good quality steel, and can be repaired via submerged arc welding at a decent crankshaft shop.

    I had a wasted rod journal fixed for a few hundred, on a few cranks.

    I do my best to save them all.

    He's got a converter and shifter. The car is already together.

    A 354 does not need more cooling than a 350.

    If the rest of the car is already ok, about the only thing it might need is a stiffer front spring.
     
    Desoto291Hemi likes this.
  11. 73RR
    Joined: Jan 29, 2007
    Posts: 7,342

    73RR
    Member


    This is factually inaccurate.
    Because the 392 has a longer stroke you lose swept volume when the 392 piston is used with a shorter stroke. The 354 actually has a larger dome volume so you will not have similar c/r in a 354, in fact it will be less. Play with the numbers if you have doubts.
    As for pistons, you can spend $500-600 for castings or around $900 for forgings and get exactly what you want. Plenty of brands to consider.
     
  12. George
    Joined: Jan 1, 2005
    Posts: 7,959

    George
    Member

    Bingo! $1,500 for a rebuildable 331 or 354 isn't bad. $2,500 on the 331 if he can get it fired up & it runs good. personally I like Cyl wall thickness, I'd do a minimal overbore, probably wouldn't notice the difference on the street. I like the 727 adaptor that QEC (77RR here on the board) makes. Don't mill heads to increase C/R. Both blocks can probably be moded to run the 392 O/P. Get the casting numbers (between head & valley cover in the back)_& use codes (on flat in front of valley cover) from both engines & post them.
     
    gimpyshotrods likes this.
  13. gimpyshotrods
    Joined: May 20, 2009
    Posts: 24,481

    gimpyshotrods
    ALLIANCE MEMBER

    I thought it would be lower, but I'm having a confusing day.
     
  14. bangngears
    Joined: Aug 30, 2007
    Posts: 1,308

    bangngears
    Member
    from ofallon mo

    If you get it to say, 300/350 hp and are using a chevy water pump be sure to have mechanical freeze plugs. Stock press in plugs will blow out, especially the passenger side middle plug. Ask me how i know.
     

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