Register now to get rid of these ads!

Hot Rods Let's talk Cadillac 331's, 365 and 390's

Discussion in 'The Hokey Ass Message Board' started by Roothawg, Apr 7, 2016.

  1. v8shadow
    Joined: Aug 20, 2016
    Posts: 13

    v8shadow


    Interesting since anywhere ive read says since a 390 is a bored out to the max 331, the 390 really cant be bored out much more.
     
  2. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,512

    falcongeorge
    Member
    from BC

    Should kinda go to show that a sonic test always trumps "what I read".
     
  3. clunker
    Joined: Feb 23, 2011
    Posts: 1,210

    clunker
    ALLIANCE MEMBER
    from Boston MA
    1. MASSACHUSETTS HAMB

    Isn't .020 - .040 standard clean up/rebuild sizes for the '59-'60 Cad motor? .02, .03, and .04 pistons and rings are available off the shelf for that 390, some companies offer .06. The machine shop should do a sonic check, but it's not like he's boring a 331 x .25 to make a 390. I'm not sure of the min wall thickness, but if those over bores are available wouldn't a sonic test be expected to check out ok unless there is something unusual? Maybe I'm wrong.
     
  4. Roothawg
    Joined: Mar 14, 2001
    Posts: 17,094

    Roothawg
    Member

    I think mine will need at least .030. As far as I know, that's pretty standard.
     
  5. Roothawg
    Joined: Mar 14, 2001
    Posts: 17,094

    Roothawg
    Member

  6. Jalopy Joker
    Joined: Sep 3, 2006
    Posts: 17,635

    Jalopy Joker
    Member

    how about this one in Sacramento, Ca parts store? 1029161742.jpg 1029161740.jpg 1029161740a.jpg
     
    TERPU, Moriarity, Roothawg and 2 others like this.
  7. falconsprint63
    Joined: May 17, 2007
    Posts: 2,205

    falconsprint63
    Member
    from Mayberry

    my 365 was bored .030 with no issues, I don't know that I'd be comfortable at more than .040.

    the issue with the pistons I mention has to do with the collar on piston itself. I used a 390 crank after I'd already found pistons. when the shop assembled it the engine wouldn't turn through because of the interference. the 390 pistons is shorter or the wrist pin in a slightly different place. can't recall right off. the 390 heads, as mentioned are preferred direct exchange and breathe better.

    Sent from my SM-G920R4 using The H.A.M.B. mobile app
     
    Last edited: Nov 1, 2016
  8. Roothawg
    Joined: Mar 14, 2001
    Posts: 17,094

    Roothawg
    Member

    I am glad I found a 62 390. It has the full oiling system and the optimum rod/piston setup. It's basically like a factory stroker motor.
     
    warbird1, clunker and Moriarity like this.
  9. Roothawg
    Joined: Mar 14, 2001
    Posts: 17,094

    Roothawg
    Member

  10. Roothawg
    Joined: Mar 14, 2001
    Posts: 17,094

    Roothawg
    Member

  11. Roothawg
    Joined: Mar 14, 2001
    Posts: 17,094

    Roothawg
    Member

    I am looking for information on anyone that has converted a later 390 to a stick bell housing and flywheel. I really wanna use a manual transmission, so I can row them gears!
     
    Moriarity and warbird1 like this.
  12. Johnboy34
    Joined: Jul 12, 2011
    Posts: 736

    Johnboy34
    Member
    from Seattle,Wa

    My son bought adapter pieces 6 or 7 years ago, plate on the block, one on the crank, I think 1" thick, made it Chevy and he has a tko 5 speed behind it. I'll have to check with him to see where it came from.
     
  13. Roothawg
    Joined: Mar 14, 2001
    Posts: 17,094

    Roothawg
    Member

  14. Johnboy34
    Joined: Jul 12, 2011
    Posts: 736

    Johnboy34
    Member
    from Seattle,Wa

    I seam to remember something about the Cad had no hole in the crank for the pilot bearing.
     
  15. Roothawg
    Joined: Mar 14, 2001
    Posts: 17,094

    Roothawg
    Member

    I think you are correct on the later models. I wonder what flywheel everyone is using. Automatics are easier, but anyone can do that.
     
  16. Johnboy34
    Joined: Jul 12, 2011
    Posts: 736

    Johnboy34
    Member
    from Seattle,Wa

  17. Roothawg
    Joined: Mar 14, 2001
    Posts: 17,094

    Roothawg
    Member

    rust and warbird1 like this.
  18. Roothawg
    Joined: Mar 14, 2001
    Posts: 17,094

    Roothawg
    Member

    So lately I have been seeing ads for manifolds that reference Caddy and Olds engines. Do they interchange? If so, what years and what configurations? There's a 6x2 log manifold on CL that the guys is swearing will interchange with an early Olds. I have never heard of such.
     
    Last edited: Dec 9, 2016
    rust likes this.
  19. HiHelix
    Joined: Dec 20, 2015
    Posts: 353

    HiHelix
    ALLIANCE MEMBER

    Didnt some of the 60 390 Caddys come with custom 3 barrel rochester carb?
     
  20. clunker
    Joined: Feb 23, 2011
    Posts: 1,210

    clunker
    ALLIANCE MEMBER
    from Boston MA
    1. MASSACHUSETTS HAMB

    58-61 tri power Rochester 2g's, 55-57 dual quad Rochesters or Carters. Any of them will bolt onto '49-'62. Either way they are said to add 20 HP, and are cast iron. Olds intakes won't work. I have a '55 Eldo dual quad on my 1960 390. I got a deal on Ebay ($300) with correct Rochesters, needing a lot of rehab. Works fine, was fun to bring back from the dead, but doesn't really add any noticeable power.

    Before that, I found and rebuilt a good 1960 4gc core for the original single carb manifold, and that one works the best. (But I still run the dual quads 'cause they're bitchin tho)

    I think Root is lookin for something a bit more "sessy", something with some age, and maybe in aluminum.

    Like these little honeys:

    IMG_1481305792.144503.jpg IMG_1481305809.034590.jpg

    Bit pricey for most people's wallets, and what fun is paying $4000 for something like that?

    Or how about this little sweety?

    IMG_1481306280.773716.jpg
     
    Roothawg, rust and Hank37 like this.
  21. chrisp
    Joined: Jan 27, 2007
    Posts: 630

    chrisp
    Member

    They don't but since they are easier to find and much cheaper, since they look very similar, I wonder if it's possible to cut and weld one up to change port spacing to make it fit?
     
  22. TERPU
    Joined: Jan 2, 2004
    Posts: 2,048

    TERPU
    Member


    Hello and Happy Holidays RootHawg,

    Call Squeek Bell in Bako. I used his adapter and an Olds/Cadillac Scheiffer Flywheel. Squeek's stuff works great and he stands behind his parts. The conversion wasn't really hard once I found the right mix and match. Clutch is a 10" in front of a Muncie. Don't skimp on the Trans because the Cadillac loves to tear the teeth off the input, second gear, third gear etc. they are Torky and flat ass will tear up the lighter duty stuff. Oh yeah - Dual Quads get my vote :)

    All the best, Tim
     
    Roothawg and falconsprint63 like this.
  23. desotot
    Joined: Jan 29, 2008
    Posts: 1,623

    desotot
    ALLIANCE MEMBER

    I once had a 390 Cadillac and it wasn't very fast, course the car weighed in at 5,996 lbs.
    [​IMG]
     
    Roothawg likes this.
  24. desotot
    Joined: Jan 29, 2008
    Posts: 1,623

    desotot
    ALLIANCE MEMBER

    I just thought of something, I have heard that cad and Studebaker intakes interchange.That probably doesn't make anything easier but it makes for good trivia.
     
  25. chrisp
    Joined: Jan 27, 2007
    Posts: 630

    chrisp
    Member

    Port spacing is not quite the same, even if they fit it's not ideal.
     
    Roothawg likes this.
  26. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,512

    falcongeorge
    Member
    from BC

    From the photos I have seen, I would say that's an understatement.
     
    Roothawg likes this.
  27. chrisp
    Joined: Jan 27, 2007
    Posts: 630

    chrisp
    Member

    It doesn't stop people from using them, even without enlarging the ports to kind of try to match.
     
  28. Roothawg
    Joined: Mar 14, 2001
    Posts: 17,094

    Roothawg
    Member

    clunker and Bowtie Coupe like this.
  29. Jessie J.
    Joined: Oct 28, 2004
    Posts: 327

    Jessie J.
    Member

    "25. .......this 1958 triple-carb unit is a rare, one-year item. It may look like the triple-carb unit offered in 1959-1960 but is actually too narrow for interchange. When Caddy grew the 365 to 390 cubes for 1959, a taller engine block was needed to contain the 4.00-inch stroke (up from 3.63). This pushed the heads farther apart, requiring a wider intake manifold."
    This statement is inconsistent with the fact that all aftermarket 331-390 intakes are specified as fitting all 49-62 Cadillac engines.

    Also Post #112 in this thread;
    "331/365/390 deck height (crank centerline to the bock surface that the head bolts to) = 10.560" (measured) "

    The 'oddball' one year 1963 Cadillac 390 engine was the year that the deck height was lowered and the engine was narrowed by 4 inches thus requiring a narrower intake.
    This change was accompanied by many other design and engineering changes, the introduction of the front mounted distributor, and the oil pump was relocated from within the oil pan (SBC style) to a external location in the bottom corner of an entirely new for 1963 die cast aluminum front cover casting.
    (not a better idea, as aluminum wear resulted in low oil pressure requiring replacement of that entire aluminum front cover casting)
    Very few parts of the new for '63 390 engine will interchange with the 1949-62 classic Caddy 331-390 engine series.

    Sorry 'bout the bolding, couldn't get the damn thing to stop.
     
    Last edited: Feb 6, 2017

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2013 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.