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Technical 400 mopar

Discussion in 'The Hokey Ass Message Board' started by ampsbad41, Feb 21, 2021 at 8:59 PM.

  1. ampsbad41
    Joined: Jun 7, 2009
    Posts: 15

    ampsbad41
    Member
    from Texas

    I just acquired a 76 to 78 mopar trying to figure out what I have as far as something to build I guess it may have come from a motor home or a van dip stick is made into pan not sure about anything on it and don't know where to find information I have been searching the web any help is appreciated [​IMG]

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  2. Check this link for Mopar Block and Head casting numbers to help identify yours. Big blocks generally have a stamping in the block on a boss near the distributor if I recall correctly. My 413 had something like T41 on it. It's been a while, so I might be way off.
     
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  3. There's also this thread that talks about identifying Mopar Engines.
     
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  4. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 5,343

    Ebbsspeed
    ALLIANCE MEMBER

    moparts.com will help you figure it out.

    Put a 440 crank in a 400, and you've got a 451 cubic inch beast. Crank mains need to be cut a bit, and raised pin location on the pistons, but it makes for a really nice base to build power on. Those large diameter flat tappet lifters in the big block Mopar engines means you can run a lot more aggressive cam profile than pretty much any other manufacturers engines.
     
    Last edited: Feb 21, 2021 at 9:33 PM
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  5. squirrel
    Joined: Sep 23, 2004
    Posts: 47,388

    squirrel
    Member

    where you found those numbers cast into the side of the block...look on the other side, it should have the casting month/day/year.

    and find the stamped pad on the top front of the block, it will tell you more info.

    post all the numbers here. we can help you figure it out. If you take pictures of the numbers, that works too, but take good pictures so we can read the numbers on them. The one you posted is too small to see much.
     
  6. oldiron 440
    Joined: Dec 12, 2018
    Posts: 1,697

    oldiron 440
    Member

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  7. ampsbad41
    Joined: Jun 7, 2009
    Posts: 15

    ampsbad41
    Member
    from Texas

    I'm going to set on stand tomorrow sometime i need to get 50 years of oil off of it as you can see in picture i will post when I get it somewhat clean thanks for the information


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  8. George
    Joined: Jan 1, 2005
    Posts: 7,356

    George
    Member

    wasn't well received by performance people as a lo-po replacement for the nice 383. But with good C/R and cam the extra CID comes in handy.
     
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  9. oldiron 440
    Joined: Dec 12, 2018
    Posts: 1,697

    oldiron 440
    Member

    The. Only downside to the 400 is the CR it's rated as 8.2/1 but often below 8/1 making new pistons nessary for even mild performance builds.
     
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  10. Elcohaulic
    Joined: Dec 27, 2017
    Posts: 1,525

    Elcohaulic
    Member

    I remember them being decent running motors.. Maybe you can raise the compression by getting a cam that closes the intake valve sooner..
     
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  11. What are you wanting to do with it? I have one that was in a 3/4 ton pickup and did fine, it’s now freshened up and probably headed for my convertible


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  12. squirrel
    Joined: Sep 23, 2004
    Posts: 47,388

    squirrel
    Member

    Even if you know what it is, this is the most important question.
     
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  13. Yep - looks like a motor home block with those center dump exhaust - not a bad thing - like was said they are being built now by choice by the Mopar guys for those cubic inches. Fool the others into thinking it's just a 383 due to it not having the tell tell 413/440 # pad by the distributor.
     
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  14. MO54Frank
    Joined: Apr 1, 2019
    Posts: 397

    MO54Frank
    Member

  15. gene-koning
    Joined: Oct 28, 2016
    Posts: 2,173

    gene-koning
    Member

    Back in the day these motors (an I) were younger, a few buddies and myself ran a car in the hobby class at our local dirt track. We were limited to "stock" parts. I much preferred the 400 over the 383 back then. Doesn't sound like much, but with the right big block Mopar cam, the extra cubic inches helped a lot. In our area affordable 440s were pretty tough to find, but the 400s were real cheap. The 100,000 mile 400s would run 8-10 weeks at 6500 rpm. The guy at our local junk yard was selling me good running 400s for $25 each! When he got a "good one" he would set it aside for us.
    AH! The good old days! Gene
     
  16. lemondana
    Joined: Feb 21, 2009
    Posts: 124

    lemondana
    Member
    from Lincoln NE

    They make very good stroker motors. Check out 440Source.com. 500 cubic inch motor that looks like a 383!
     
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  17. ampsbad41
    Joined: Jun 7, 2009
    Posts: 15

    ampsbad41
    Member
    from Texas

    Not sure on that I have a 31 A with one in it or should I say the body is on the motor and was thinking of rebuilding this to replace that one because just about every time I fire the other one up I have to fix it to drive I don't know if cam is bad or lifters I have to always adjust them I just bought new lifters push rods and adjusters was going to try that but then this came up not sure what to do now [​IMG][​IMG]

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  18. I’m curious how you are adjusting rockers on a big block mopar?


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  19. TRENDZ
    Joined: Oct 16, 2018
    Posts: 238

    TRENDZ

    The 400 is the strongest/ best foundation for building a big block mopar. Big bore, smaller main bearings, bigger bulkheads, more compact package.
    Tough as nails. I’ve made over 1100 hp with a factory block and crank.
     
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  20. greybeard360
    Joined: Feb 28, 2008
    Posts: 1,557

    greybeard360
    Member

    451 stroker makes a great setup. You can use either 400 or 440 rods, they make pistons for both. There is a lot of discussion over which is better... One of them is a slightly longer rod (440 IIRC).
     
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  21. 400s are great for big power and very streetable of made into a stroker engine!
    I jist bought back my '67 Cuda convertible that I built in the 80s and sold 30 years ago. I have a really nice 451 for it, H beam rods, big solid lifter cam, flat tops, going for 700+ HP... depends what aluminum heads I can find used and what intake. Cant wait to get it back on the road and strip where it belongs!

    -Shiny
     

    Attached Files:

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  22. ampsbad41
    Joined: Jun 7, 2009
    Posts: 15

    ampsbad41
    Member
    from Texas

    They have adjusters on the rockers

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  23. ampsbad41
    Joined: Jun 7, 2009
    Posts: 15

    ampsbad41
    Member
    from Texas

    These [​IMG]

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  24. Ok it has aftermarket rockers then.


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  25. ampsbad41
    Joined: Jun 7, 2009
    Posts: 15

    ampsbad41
    Member
    from Texas

    No they are factory high performance is what I have found out the crane are replacements the push rods are as big as my pinky fingers and I bent one

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  26. I would like to see a picture, I’m not aware of a factory adjustable rocker for them, possibly 426 wedge stuff? I have never seen or read anything about them.


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  27. oldiron 440
    Joined: Dec 12, 2018
    Posts: 1,697

    oldiron 440
    Member

    They were sold over the counter for years. Direct Connection and Mopar Performance parts even back in the sixties.
     
    Last edited: Feb 23, 2021 at 3:34 PM
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  28. So aftermarket.


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  29. oldiron 440
    Joined: Dec 12, 2018
    Posts: 1,697

    oldiron 440
    Member

    Max wedge rockers but sold over the counter also.
     
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  30. Those look similar to my Harland Sharp adjusters .
    I always thought all the old Mopar adjusters used a slot for a screwdriver,,,,not an Allen wrench ?
    How long ago was it ?

    Tommy
     

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