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Technical standard to automatic change over question (56 Chevy Truck)

Discussion in 'The Hokey Ass Message Board' started by saltflatwilly, Jul 14, 2014.

  1. saltflatwilly
    Joined: Mar 1, 2009
    Posts: 156

    saltflatwilly
    Member
    from MASS

    I am switching a 56 Chevy truck from the original 3 on the tree to a 700R4 and I realize I have to add the tranny support however what about the mount at the bellhousing / rear of the motor? Do I need to add a support and if so, does anyone offer one off the shelf?
     
  2. dcmalone
    Joined: Jun 2, 2011
    Posts: 10

    dcmalone
    Member

    Motormounts and a trans cross member is all you need. Speedway, Classic Parts, American Classic Parts and numerous others sell a bolt in version for our trucks. You'll need to cut out the rear support that's in it now. It's riveted in but not too bad of a swap. I originally had a 3 speed manual, swapped to a TH350 and eventuallt to a 200 4R to get overdrive. The 200 is the same length as a TH350 so no driveshaft shortening. Did have to move the trans cross member back about 5 inches but that only required new mounting holes.
     
  3. squirrel
    Joined: Sep 23, 2004
    Posts: 49,295

    squirrel
    Member

    That works if you don't have the original 56 engine, which has no provisions for side mounts...

    The driveshaft yoke is a different spline.

    But yeah, it's a pretty straightforward swap
     
  4. low budget
    Joined: Nov 15, 2006
    Posts: 5,564

    low budget
    Member
    from Central Ky

    I did a 57 pickup 350/350 and only used a 70s style camaro/nova etc. type crossmember laying perfectly rite in the inside of the frame channels I just had to drill holes (as I think I remember)while using the original front stool motor mounts, I also done 2, 55 cars the same way {but had to make a couple brackets for the crossmember to attach to the frame}and got by with it but I couldnt say I would recommend it to anyone else just because it worked ok for me.

    Im not sure the setup I had would allow "a lot" of rough rodding around or you might find your engine and trans upside down in the engine bay without the side motor mounts.:D
     
    Last edited: Jul 14, 2014

  5. squirrel
    Joined: Sep 23, 2004
    Posts: 49,295

    squirrel
    Member

    might be hard on the transmission case too, it's not really designed to support the weight of the engine
     
  6. you really need side mounts with automatic transmission.
     
  7. saltflatwilly
    Joined: Mar 1, 2009
    Posts: 156

    saltflatwilly
    Member
    from MASS

    Does anyone know if there is any suppliers that sell the side mounts already?
     
  8. 325w
    Joined: Feb 18, 2008
    Posts: 5,609

    325w
    ALLIANCE MEMBER

    Pickup frame is sorta wide. Need a crossmember to reach over to the other side the reach up and tie to the motor. Lots of those out there.
     
  9. low budget
    Joined: Nov 15, 2006
    Posts: 5,564

    low budget
    Member
    from Central Ky

    Found these side motor mounts for your truck on ebay with just a quick search and sevral pics of others all over the net, not sure about the bell housing mounts without looking but I think you may hafta cut that bellhousing xmember out as suggested earlier,thats what I did to the 57 as well.

    Ecklers,harmons,speedway and others may have them I havent looked.

    By the way the camaro/nova trans crossmember does fit rite in the frame channel as I remembered, I have a extra xmember out in the garage and layed it between the frame rails on the 55 truck out there just to make sure I remembered correctly.
    [​IMG]
     
    Last edited: Jul 15, 2014
  10. squirrel
    Joined: Sep 23, 2004
    Posts: 49,295

    squirrel
    Member

    That mount shown above will eventually crack the frame. Use a tubular crossmember type mount instead.
     
  11. low budget
    Joined: Nov 15, 2006
    Posts: 5,564

    low budget
    Member
    from Central Ky

    Where do they crack the frame? does it matter if you only have mild horsepower or would it help to weld em in?
     
  12. squirrel
    Joined: Sep 23, 2004
    Posts: 49,295

    squirrel
    Member

    The frame is a channel shape, the mount puts a torque on the frame. A crossmember just puts a vertical load on the frame, not a torque.

    I'm just telling you about my experience with that type of mount on that type of truck. It's not good.
     
  13. mphudak
    Joined: Jul 30, 2010
    Posts: 176

    mphudak
    Member
    from Atlanta

    What motor do you have in the truck?

    Posted using the Full Custom H.A.M.B. App!
     
  14. saltflatwilly
    Joined: Mar 1, 2009
    Posts: 156

    saltflatwilly
    Member
    from MASS

    327 chevy. I found on LMC truck parts this:
    34-0305UNIVERSAL FRAME MOUNT KIT
    But it doesn't have much of a description
     
  15. squirrel
    Joined: Sep 23, 2004
    Posts: 49,295

    squirrel
    Member

    Yeah, that's the type I recommend. Should be the same as the TransDapt one.

    Did you say whether or not your engine has the bolt holes on the sides, for the side mounts? If it's a 58 or newer engine, it should have them. If it's an original 56 engine, it won't.

    lmc.jpg
     
  16. saltflatwilly
    Joined: Mar 1, 2009
    Posts: 156

    saltflatwilly
    Member
    from MASS

    its a newer 60's 327
     
  17. Bubba1955
    Joined: Jul 8, 2013
    Posts: 463

    Bubba1955
    Member

    I used to have a '55 Chevy P.U. with a Muncie 4 speed and considered switchng to an auto. (never did), but wondered if taking out the original trans crossmember would compromise the ridgidity of the frame....Anyone?
     
  18. squirrel
    Joined: Sep 23, 2004
    Posts: 49,295

    squirrel
    Member

    It does compromise it a little bit, but it doesn't seem to be an issue.
     
  19. Bubba1955
    Joined: Jul 8, 2013
    Posts: 463

    Bubba1955
    Member

    Just wondered because I've heard if you change to IRS, maintaining frame rigidity is even more important.
     
    Last edited: Jul 16, 2014
  20. Gerry Moe
    Joined: Jan 29, 2006
    Posts: 498

    Gerry Moe
    Member

    This mount will work but will require boxing of the frame approx 9 inches in each direction of centerline of mount. I would also recommend gusseting the ends of the 90 degree w/the two holes. As long as the front cross member (radiator and front sheet metal support) has not been altered a cross pc under oil pan will not be needed, it would put your worry to rest if you did incorporate it. If I chose to use the full cross member I would not use these mounts and fab my own, or use #5 & #6 as Jim Forbes (Squirrel) above posted along with #8 for the trans.
     

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