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Tech Info: Cadillac OHV V8's 1949-1962

Discussion in 'The Hokey Ass Message Board' started by Cadillacin Marcus, Jan 19, 2004.

  1. I built a 331 Caddy with a 4 " bore and a 3/8 inch steel stroker kit using 12:1 pistons back in 1965 and I'm still running it today. Backed up with a GTO close ratio and Olds. rear packed into a 37 Ford cp.
     
    ls1yj likes this.
  2. Marcus , I got a Hilborn injection setup and a 49 Horne 4-2 intake that I ran at stages in my Caddy build up from back in 1965.
     
  3. When I did the PCV installation on my 331 I cut the road draft tube off just outside of the elbow that attaches it to the valley cover. Then welded a correct dia. washer to the end of the tube and welded half of a pipe coupling over the hole. If you have access to a lathe you could turn out a fancy adapter to go from the I.D. of the tube to female NPT. The adapter I welded up works fine and its hidden down below the intake manifold so isn't noticable. Into this adapter goes a pipe to hose fitting. I installed the PCV valve into the manifold vacuum port on the secondary side of the front WCFB. You could do the same, or just plumb it into the vacuum port on the manifold. I used a PCV valve p/n FV100, which I think is a Fram part number. Have your parts guy do a search for the PCV valve for a '61 Cad, which is what I did. Then it's just a matter of rounding up the correct brass pipe fittings, hose and hose barb to make the system work.

    Hardest thing on my installation was drilling out the manifold vacuum connection on the back of the WCFB from 1/8 NPT to 1/4 NPT. Not a lot of extra meat there, but it worked.


    Hope this helps...
     
  4. Barrelnose pickup
    Joined: Aug 20, 2008
    Posts: 986

    Barrelnose pickup
    ALLIANCE MEMBER

    excellent info in this post,pcv and crank sealing but the cam in my early 49 has a spring loaded thrust set up which I am told only was around for the first couple months of production as was the rocker cover centre mounts.Is this correct or should this newbie be silent?If I am correct maybe someone can tell me if the later cams are interchangable,thanks,still learning.
     
  5. r8odecay
    Joined: Nov 8, 2006
    Posts: 787

    r8odecay
    Member



    my learnings are early 49 has a spring loaded cam, and no they are not interchangable w/ later cams. Kanter Auto has stock grind replacements...hope this helps
     
  6. Barrelnose pickup
    Joined: Aug 20, 2008
    Posts: 986

    Barrelnose pickup
    ALLIANCE MEMBER

    Thanks r8odecay,I will try and find Kanter Auto on the web.
    Thanks again,
     
  7. What year front timing cover started to use a rubber seal? What is ment by later front cover? Does anybody know?


    CBB
     
  8. bushwacker 57
    Joined: Oct 3, 2007
    Posts: 475

    bushwacker 57
    Member

    On the front timing cover i would say late 1956 and up.
     

  9. I'd guess that bushwacker is correct. My '55 motor still uses the felt seal in the front cover. It actually seems to work well, but what a pita to get the seal into the cover:(
     
  10. bushwacker 57
    Joined: Oct 3, 2007
    Posts: 475

    bushwacker 57
    Member

     
  11. falconsprint63
    Joined: May 17, 2007
    Posts: 2,358

    falconsprint63
    Member
    from Mayberry

    marcus--great thread and good to find you out in cyber land again. here's pics of my 48 sedan delivery. thanks to all your help and parts several yeas back I can say I ran out of the back strech at charlotte speedway before I ran out of third gear. nothin says hot rod like a cadillac!

    matt in SC (formerly Iowa and NC)
     
  12. _charles_
    Joined: Feb 13, 2007
    Posts: 305

    _charles_
    Member
    from Tampa, Fl

    Does ANYBODY know where the extra compression came from between the 331/365/390 motors? Was it the pistons or the heads? (or both)

    I have a rebuilt 331...but I also have some 390 heads on the shelf. Wondering how high my compression will go if I slap the 390's on. currently at 8.25:1

    Charles
     
  13. Thanks for info! Speed parts are hard to find info seems even more difficult.
     
  14. FSHTNK
    Joined: Apr 8, 2008
    Posts: 75

    FSHTNK
    Member

    Can i just bump this, i'm interested as well in using a set of 390 heads on my 331 (anyone got some? PM or email me)
    I have searched but I can't pin down the difference's betwwen the heads valve sizes, and Combustion chambers.
    Who's the expert :confused:

    I also remember reading that the later (redesigned) 390 from what, 62? on are also compatible. ie, the heads on these will fit 331/365/390's. Can anyone confirm?

    Cheers guys, trying to make a Down Under Caddy sound Shweet!
     
  15. c322348
    Joined: Nov 28, 2007
    Posts: 308

    c322348
    Member

    Well, here's a little spreadsheet I put together today:



    Hopefully some will find it useful.

    <EDIT> Though I have yet to run my new engine, the early 390 head fits fine onto the 331 short block. Reports from others indicate this has been done successfully for years.

    The 390 heads require significant porting BTW. Look in my "New Skool Caddy" thread for info.
     

    Attached Files:

    Last edited: Sep 29, 2017
    sproadster30 likes this.
  16. FSHTNK
    Joined: Apr 8, 2008
    Posts: 75

    FSHTNK
    Member

    Awesome! Any info on valve sizes? That '58 365 head is interesting. If that has, or can take the larger 390 valves, that would be the head to have alright.
     
  17. c322348
    Joined: Nov 28, 2007
    Posts: 308

    c322348
    Member

    The info I have is that the '58 had 1.75 Intake/1.562 Dia. Exhaust Valves and the 59-67 used 1.875 Intake/1.50 Exhaust Valves. 58-62 used a stem height of 2.030-2.060. Head casting number 1473449 appears to be used from 58-63.

    Some of the articles I've seen recommend installing SBC valves (1.92/1.50).

    59-62 should be essentially the same as the '58, so I wouldn't discount those.

    Make sure you check out the Hot Rod Deluxe article (http://hotrodcaddy.com/?p=139) if you haven't already. It says that the 390 chambers are 66cc which differs from my numbers a little. Maybe the compression height and head gasket thickness throw off my calculated numbers a bit.
     
    Last edited: Feb 4, 2011
  18. falconsprint63
    Joined: May 17, 2007
    Posts: 2,358

    falconsprint63
    Member
    from Mayberry

    with the 390 heads you can fun 1.94 and 2.02 SBC if I recall correctly.

    I've always been told the 390 heads are the ones you want
     
  19. Would love to see more info!!!
     
  20. Torkwrench
    Joined: Jan 28, 2005
    Posts: 2,441

    Torkwrench
    Member

    Have been seeing a few early Caddy tech questions, lately. So, here's a bump to an excellent Caddy tech thread. :cool::cool::cool:
     
  21. BillyBob
    Joined: May 9, 2005
    Posts: 24

    BillyBob
    Member

    Very good info!
     
  22. Koops
    Joined: Apr 17, 2001
    Posts: 243

    Koops
    Member

  23. M.Edell
    Joined: Jun 5, 2009
    Posts: 4,153

    M.Edell
    Member

    haha..Wow..I forgot most of this stuff I wrote its been so long ago..Glad people find it useful still..
     
  24. GARY T.
    Joined: Mar 23, 2008
    Posts: 1,984

    GARY T.
    Member
    from S.W. Pa

    Something ain't right on your chart---the 58 had 365 ci the 59-62 had 390 ci:eek:
     
  25. r8odecay
    Joined: Nov 8, 2006
    Posts: 787

    r8odecay
    Member


    the top half of the chart shows the stock stuff, the bottom half shows the resulting compression when you swap around diff years stock stuff...what you are reading is the CR gains of putting a '58 365 head on a 59-62 390 block... theoretically should be 11:1.
     
  26. c322348
    Joined: Nov 28, 2007
    Posts: 308

    c322348
    Member

    Correctomundo!

    Please see note #7 on my chart also. If anyone has info on the different pistons used I can expand the chart to include that info.

     
  27. r8odecay
    Joined: Nov 8, 2006
    Posts: 787

    r8odecay
    Member


    Thank you for putting the effort forward in that spreadsheet...

    My aftermarket replacement 365 pistons came in as flat-tops, although I see the 1958 and up pistons have a 'dish' (more like an ice cream scoop) across the centerline of the piston, not circumferential....
    [​IMG]
    Not sure if this completely answers the mail in your #7, aftermarket pistons are sure to differ greatly...
     
  28. c322348
    Joined: Nov 28, 2007
    Posts: 308

    c322348
    Member

    Are the top of your pistons flush with the deck of the block?

    If anyone has a set of those dished pistons and has a way to measure the displacement I think it would be helpful!

    This is a great thread!

     

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