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Hot Rods Cadillac 365/390 intake dowels, do I need them?

Discussion in 'The Hokey Ass Message Board' started by Roothawg, Oct 18, 2019.

  1. Roothawg
    Joined: Mar 14, 2001
    Posts: 18,730

    Roothawg
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    So, I have an aluminum Weiand early 2x4 Caddy intake. Over the years the dowel has worn a hole in the intake. I was going to weld up the holes and redrill, but then I started to wonder if I even need them?

    Were they just because the old intakes weighed 60 lbs? Or do they actually have a function, like holding the gaskets in place?

    I just need to get this done, so I can get it to the polisher.
     
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  2. Roothawg
    Joined: Mar 14, 2001
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    Anyone? Bueller? Bueller?
     
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  3. ss34coupe
    Joined: May 13, 2007
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    I have wondered the same thing about my Cragar 6 carb manifold. Does not have the holes for the dowel pins on the heads, so to use this rare manifold I would have to cut the dowel pins off. Not a big deal if they don't serve any real purpose.
     
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  4. BJR
    Joined: Mar 11, 2005
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    They must help line up the ports or Cadillac would not have put them in there in the first place.
     
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  5. Budget36
    Joined: Nov 29, 2014
    Posts: 2,300

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    I kinda figure if it had it, then use it. I mean would a place add something to the product that cost money if it wasn't needed/warranted?
     
  6. Mr48chev
    Joined: Dec 28, 2007
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    Remembering back to the dark ages and doing a valve job on one of those in a big 4 door sedan in the early 70's those dowel pins sure were nice for keeping things in place.
    Do you absolutely need them, no they just make things a lot easier when it comes to keeping gaskets in place and getting the manifold down square. No doubt a whole lot harder with the cast iron monster than with the aluminum unit.
    can you grab the pins with a good pair of vise grips and pull them out? They were driven in at one time and one should be able to pull them out.
     
  7. Roothawg
    Joined: Mar 14, 2001
    Posts: 18,730

    Roothawg
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    I guess my question is this: Do I need to go to all the trouble of filling the holes back and redrilling? They are close to the ports and I was going to surface the intake a bit afterwards to true up the gasket face. These holes have been hogged out over the years, so I doubt there is much value left. The precision is gone.

    As far as lining up the ports, I would think if the bolts don’t do that, you have bigger problems.
     
  8. Roothawg
    Joined: Mar 14, 2001
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  9. I have no experience with Cadillac stuff but every dowel pin I have seen is there for locating during assembly, pictures for those of us not familiar with it may help.


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  10. Roothawg
    Joined: Mar 14, 2001
    Posts: 18,730

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    OK. I have pics of the intake. I'll have to get pics of the heads later.
    IMG_1773.jpg IMG_1776.jpg
     
  11. Looks to me like because the bolt holes appear to be slotted it may be more of a challenge to get it positioned without them but once tight there would be no need for them. I would not worry about them if it was mine


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  12. lumpy 63
    Joined: Aug 2, 2010
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    My thinking is there is a whole lot of variables involved in those dowel pins...Deck height , amount heads have been milled and head gasket thickness. Caddys came with steel shim head gaskets , way thinner than than later composite gaskets. When I received my new Offy intake it didn't quite drop onto the dowel pins. I upsized the holes in the manifold and it fit better . When I tore the motor down It had been rebuilt in its past , thicker gaskets etc. So at this point I'm going to wait until the engine is assembled and check the fit at that point , but yes I will retain them.
     
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  13. lumpy 63
    Joined: Aug 2, 2010
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    Although I did just get an NOS GM top end gasket kit .:cool:
     
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  14. Roothawg
    Joined: Mar 14, 2001
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    I think these may have been slotted originally. I need to weld it up and surface the manifold flange.
     
  15. lumpy 63
    Joined: Aug 2, 2010
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    Honestly Root I would wait till your longblock is assembled and lay it up on the engine to see what has been done in it's past as far as angle milling etc. But in reality the dowel pins are not a deal breaker.
     
  16. Roothawg
    Joined: Mar 14, 2001
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    Well, here's the deal. I wanna take it to the polisher, but I don't wanna hafta repolish later. If I have someone weld up the hole, I just want to see if I need to redrill the hole. I guess I can weld it up and fill it. Make a decision at a later date on drilling the intake.
     
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  17. The later Weiand 2 X 4 has slots, yet the Weiand 6 X 2 DragStar has holes o_O
     
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  18. Roothawg
    Joined: Mar 14, 2001
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    Good info to have.
     
  19. Interesting... my early Weiand 2 X 4 also has the slots.
     
  20. Moriarity
    Joined: Apr 11, 2001
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    My Weiand 2x4 has holes and I would certainly think you don't need the pins as the gasket should locate fine on the ctr 2 studs.....

    E25B9B47-19AE-4AD8-894E-B654AEF409EF.jpeg AFEE906B-C6FD-4589-B7AA-22BB77D29289.jpeg
     
  21. Atwater Mike
    Joined: May 31, 2002
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    I worked at Cadillac/Oldsmobile dealer in 1962, started out as a 'line mechanic'. Re-installed many intake manifolds after head gasket replacements, sometimes heads were 'fly-cut', always minimal amount.
    Never an issue with dowels interfering with manifold seating, dowels just 'seemed to assure that bolts would align'!
    I was promoted to 'Carburetor man' after old Ron retired...Much better job, as far as the heavy Cad parts and lifting went...and the cleaning, and scraping...Agggh! Memories.
     
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  22. Roothawg
    Joined: Mar 14, 2001
    Posts: 18,730

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    If you look at this picture, you can see it started out as a slot and eventually someone drilled it. I'm just not comfortable leaving this little amount of edge distance, next to the port.

    IMG_1776.jpg
     
  23. Would be hard to line up heavy stock manifolds without dowels .
     
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  24. Moriarity
    Joined: Apr 11, 2001
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    Moriarity
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  25. Moriarity
    Joined: Apr 11, 2001
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    Offy 3x2 has slots

    352AE925-00D5-4A8C-B0D1-5944CBDD082C.jpeg

    Weiand 3x2 has holes and look how close to the port ... and look at the core shift!!

    07756CA9-601F-48FD-818D-93B4CB054E81.jpeg
     
  26. lumpy 63
    Joined: Aug 2, 2010
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    My new Offy 3x2 definitely has holes not slots ...So maybe the changed the design on the new one's Mark?
     
  27. Moriarity
    Joined: Apr 11, 2001
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    Moriarity
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    they must have, mine is an original and has slots that go thru
     
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  28. The later intake is not quite as sexy as its earlier version...:rolleyes:
    20170330_094953_HDR (2).jpg
     
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