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Customs Caddy motor question

Discussion in 'The Hokey Ass Message Board' started by caddyguy, Mar 19, 2017.

  1. caddyguy
    Joined: Aug 29, 2005
    Posts: 37

    caddyguy
    Member
    from canada

    Hello, I have a 331 caddy motor with 390 heads. I've placing it back in the 55 caddy but I cannot use the 390 exhaust manifolds. Drivers side hits the steering box, passenger side hits the "a" arm bolts, because of the generator bracket. I don't want to use the 331 manifolds as they are restrictive and the gaskets will not seal the ports properly. I'm thinking to purchase the Sanderson Headers, c-391. I don't know if they will work so I am wondering if anyone else has done this mod to the 331 motor and what did they use for the exhaust manifolds? I know I will have to make a generator bracket for these.
    Any ides would be great. Thanks, George.
     
  2. steinauge
    Joined: Feb 28, 2014
    Posts: 1,507

    steinauge
    Member
    from 1960

    I do not know if the Sandersons will fit in a 55 Caddy,maybe ask Sanderson? .I do know if you put in a few hours porting and cleaning up the 331 manifolds they will work a lot better and cost nothing but time.Not the ideal situation but better than nothing if you cannot modify the 390 manifolds to fit.
     
  3. Roothawg
    Joined: Mar 14, 2001
    Posts: 20,102

    Roothawg
    Member

    I thnk the Sandersons fit all of the 331-390's.
     
    loudbang likes this.
  4. clunker
    Joined: Feb 23, 2011
    Posts: 1,613

    clunker
    ALLIANCE MEMBER
    from Boston MA
    1. MASSACHUSETTS HAMB

    Another member was trying to do something similar last year in a '55. I think it was a 331 block with 390 heads (I could be wrong) He was trying to find out if using a passenger side manifold on both sides would work (they exit center and strait down). Some people chimed in and said that's what they do in their non- Cads for clearance.



    Probably a different situation to yours, but maybe there's some good info. He never came back to tell us how it went. It might be better to start with headers.

    Here's the link if you care to read it:

    http://www.jalopyjournal.com/forum/threads/365-390-exhaust-manifold.1033647/
     

  5. caddyguy
    Joined: Aug 29, 2005
    Posts: 37

    caddyguy
    Member
    from canada

    I will modify the passenger side to fit that I have from the 390. I bought a 57 passenger side exhaust manifold and will see if it will work. They are both centre dumps.
     
    clunker likes this.
  6. samurai mike
    Joined: Feb 24, 2009
    Posts: 466

    samurai mike
    Member

    i had the same problem putting a 390 in a 54 cadillac. i solved the problem by putting the 390 in a 1928 dodge!
     
    clunker likes this.
  7. Kirby50
    Joined: Nov 4, 2012
    Posts: 14

    Kirby50
    Member
    from san diego

    Not to bring up an old thread but what did you ever do to fix your problem Caddyguy? I'm looking at 390 heads now for a 331 that will go back into a '53 caddy.
     
  8. caddyguy
    Joined: Aug 29, 2005
    Posts: 37

    caddyguy
    Member
    from canada

    I used the passenger exhaust manifold from a 56 caddy (365 motor) as it has the right size ports and discharge. Then exhaust manifold off a 390 passenger side for the drivers side. This side is a bitch to get on and close to steering box. Thats as far as i got. No time to carry on with my car. Hope this helps
     
  9. Kirby50
    Joined: Nov 4, 2012
    Posts: 14

    Kirby50
    Member
    from san diego

    Yes it does, more parts to look for! lol. Hope you find the time soon to finish it and enjoy the car!
     

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