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will my 39 plymouths rear hold up to a 351w?

Discussion in 'The Hokey Ass Message Board' started by malaguena, Mar 17, 2012.

  1. So ive a 39 plymouth p8, plym and dodge supposedly used the same rear from 38 through 52. Now if theyd hold up to small hemis in the dodges. Im thinking i can just fix my plyms rear brakes and drop this stock 351w and c4 into her.
     
  2. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,445

    Rusty O'Toole
    Member

    It will stand up as long as you don't floor it away from every stop sign. But what are you going to do for an emergency brake?

    Might as well plan on a new rear axle. The old one has a lousy gear ratio anyway (too low, like 3.9:1). I hear a Jeep Cherokee axle is the right width.
     
  3. well the emergency brake cable goes to the rearend. I figured that would be fine.
     
  4. AnimalAin
    Joined: Jul 20, 2002
    Posts: 3,417

    AnimalAin
    Member

    It will work fine, right up to the time is fails catastrophically.
     

  5. George
    Joined: Jan 1, 2005
    Posts: 7,369

    George
    Member

    The 241 Dodge hemi didn't come out untill '53, maybe why the axle was dropped @ the end of '52.....even then the 241 was only rated @ 140 HP. There's a number of newer axles that'll work with a perch location change.
     
  6. 35desoto
    Joined: Oct 6, 2009
    Posts: 762

    35desoto
    Member

    If your diff has the emergency handbrake cables going to it then its not the original diff. These had a cardon shaft handbrake attasched tom the rear of the geaRBOX AND ONLY THE FOOT HYDRALICE BRAKE WORKED IN THE THE DIFF
     
  7. George
    Joined: Jan 1, 2005
    Posts: 7,369

    George
    Member

    You have a late 70s smogger? 69-early 70s with decent power came with FMX.
     
  8. RodStRace
    Joined: Dec 7, 2007
    Posts: 2,471

    RodStRace
    Member

    My 2 cents, I'd swap rear ends.
    You will gain better gears, E brake, better brakes (self energizing drum or disc) and no more tapered ends!
    All of that and more peace of mind.
     
  9. RiKi5156
    Joined: Feb 5, 2011
    Posts: 42

    RiKi5156
    Member

    A stock c-body rearend such as 67-8 chrysler will drop right on your stock springs and is plenty strong. You can fit a 235 or 245 width tire. It usually comes with 2/12 by 11 drums. Rich
     
  10. squirrel
    Joined: Sep 23, 2004
    Posts: 47,791

    squirrel
    Member

    Can you post some pictures of the rearend? it might not be original
     
  11. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,445

    Rusty O'Toole
    Member

    If the rear axle has Ebrakes on it , it is not original. Maybe someone put a newer rear axle in there already. You never know your luck. Chrysler cars used the transmission Ebrake up to 1962 maybe 1964. So if it is a Chrysler rear end it must be newer than that. Are the back wheels held on by bolts or nuts?
     
  12. The37Kid
    Joined: Apr 30, 2004
    Posts: 27,802

    The37Kid
    Member

    Does the car still have the 1939 Master Cylinder mounted in the stock location? If so you'll want to join the others and track down the guy that designed it.
     
  13. well im using the 351w and c4 out of a 79 ford f100. I dont know what the rear from the 79 truck is, but i suppose im stuck using it. But its perhaps 6 inches wider that the "39" rearend.
     
  14. You're not stuck using it. Find a rearend that is the right width.
     
  15. George
    Joined: Jan 1, 2005
    Posts: 7,369

    George
    Member

    As has been said, post pics on the current axle, sounds like it is newer than stock, may be just what you need, even a little 71/4 may work with a '79 351W/C4.
     
  16. 73RR
    Joined: Jan 29, 2007
    Posts: 6,538

    73RR
    Member

    WOW! and you actually think about using it?

    As previously mentioned, if the axle in the car has an e-brake, as you said, then identify what it is before doing anything else.

    .
     
  17. 4woody
    Joined: Sep 4, 2002
    Posts: 2,101

    4woody
    Member

    A Ford 8" out of a Granada will fit, is strong enough, and has the right bolt pattern.
     
  18. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,445

    Rusty O'Toole
    Member

    What rear axle is in the car now? You may be in luck. Somebody already changed it so you don't have to.

    Check the gear ratio by turning the wheel and counting the revolutions of the drive shaft.

    Give us a picture and the pumpkin heads will tell you what it is out of. A picture of the center section and a picture of the wheel hub.
     

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