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Projects 39 Pontiac Coupe (series 25 small body) build

Discussion in 'Traditional Hot Rods' started by AGELE55, Dec 7, 2019.

  1. AGELE55
    Joined: Jan 4, 2018
    Posts: 235

    AGELE55
    Member

    So my 39 Poncho frame used to be an X frame, but a PO cut out the X. The rest of the frame looks solid. I would love to find a Pontiac 326 cui (may settle for sbc) and probably run an automatic tranny.
    -Any advice on what I need to do to salvage this frame and/or beef it up?
    -Assuming the rear end is decent, will it handle the load?
    -The front suspension has the old funky shocks...worth keeping? 20191207_150017.jpg 20191207_150039.jpg 20191207_150048.jpg
    Gotta start somewhere... Thanks
     
    kidcampbell71 likes this.
  2. Sporty45
    Joined: Jun 1, 2015
    Posts: 953

    Sporty45
    Member
    from NH Boonies

    Where are you located? I know a guy by me that had a 326 for sale, but don't know for sure if he still has it.
     
  3. AGELE55
    Joined: Jan 4, 2018
    Posts: 235

    AGELE55
    Member

    I'm in the Jacksonville Florida area. Looks like you're in NH, so not thinking you can mail it...lol
     
    Sporty45 likes this.
  4. oldtom69
    Joined: Dec 6, 2009
    Posts: 538

    oldtom69
    Member
    from grandin nd

    Got to assume the reason you want to use this frame is that you have a very nice 39 Pontiac body to go with it??
     

  5. Sporty45
    Joined: Jun 1, 2015
    Posts: 953

    Sporty45
    Member
    from NH Boonies

    Yeah, probably not very cost effective! :p
     
  6. ROADSTER1927
    Joined: Feb 14, 2009
    Posts: 2,889

    ROADSTER1927
    Member

    Mock up what ever power train you end up with then jus reinforce as needed. It is just like stating with a couple rails.
     
    1934coupe and 427 sleeper like this.
  7. RJP
    Joined: Oct 5, 2005
    Posts: 1,799

    RJP
    Member
    from PNW

    disassemble it, blast it, square it, clamp it, box it, make a square tube tranny mount, square tube driveshaft loop, mounting both off the boxing plates. easy peasy, lemon squeezy.
     
  8. mgtstumpy
    Joined: Jul 20, 2006
    Posts: 8,720

    mgtstumpy
    Member

    If it were mine I'd source another frame or look for a damaged one (Other similar YOM GM platforms) just for the X-member. As suggested mock up your drive train with body on at least before you add any additional members. In the end you want to minimise all the torsional twist that the X-member was designed for.
    As an example I used a complete [Slightly modified] 46 Olds X-member with trailing arm suspension in a friend's 42 Chevy PU. All I did was step up the rear frame slightly and add coil-overs with a 9".
    Eg. I've 34 frame under my 35 Chevy and replicated the OEM X-member with double row tubing. 'Solid as' now when driven compared to 34 ladder frame that twisted with every bump in the road.
     
    Hnstray likes this.
  9. Hnstray
    Joined: Aug 23, 2009
    Posts: 11,969

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    I agree your stock rails look solid. Buick, Olds and Pontiac all used very, very similar chassis from at least 1937 thru the late '40s and into the '50s. Finding one of them should not be terribly difficult and would give you sufficient material to reconstruct your 'X' member.

    Another choice, easy to source, a '60s thru '72 GM pickup chassis.....the center cross member is pressed channel and pretty beefy as it was used as an attach point for the suspension arms. Not suggesting you use suspension arms.....only the cross member. From that base, pressed channel (not channel iron...pressed channel has consistent thickness and the flanges are rounded) sections to the original X member stubs.

    There are alternatives, but this would replicate the original and restore the beam and torsional strength.

    edit: @mgtstumpy types faster ;)

    Ray
     
    Last edited: Dec 7, 2019
    427 sleeper, flatford39 and mgtstumpy like this.
  10. jetnow1
    Joined: Jan 30, 2008
    Posts: 1,779

    jetnow1
    ALLIANCE MEMBER
    from CT
    1. A-D Truckers

     
  11. Hnstray
    Joined: Aug 23, 2009
    Posts: 11,969

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Yes, you are correct about early '39 Buick chassis being 'shortened' after the rear axle.......but that was a partial year situation. In prior years, '37 was leaf sprung, but had an X frame.....'38 and all successive models into the early '60s were coil sprung and X member frames.

    In any case, I seem to be missing your point, and would welcome a clarification.

    Ray
     
  12. bill gruendeman
    Joined: Jun 18, 2019
    Posts: 504

    bill gruendeman
    Member

    i have a 39 Pontiac also. The frame rails are like 6 or 6 1/2 inch’s tall and is very strong. I see the front of the x member is still there and the tail mounted by the front of the leaf springs, get some 5 inch channel ( stamped not hot rolled channel iron ) and make an x member more like a 40 Ford would have. I replaced the rear end and springs with a 79 trans am good fit and not hard to make mounts. i also clipped the front with a 79 trans am but the stock front end has disc brakes and replacement parts available, I have heard. you may know or not your frame is “big car” models 26 and 28 Pontiac also made small body (25) , a Chevy with a pontiac front end, no parts interchange but look the same as big body’s.
     
    Last edited: Dec 7, 2019
    flatford39 likes this.
  13. flamedabone
    Joined: Aug 3, 2001
    Posts: 4,908

    flamedabone
    Member

    Don't you dare put a goddam small block Chevvie in that car. I drove through Jacksonville today, had I known you needed a Pontiac motor, I would have dropped one off to you.

    As for the frame, a local fab shop can bend some 1/8X 5 channel for you. Look at a picture of a stock frame and make it look like that. It doesn't have to be 100% identical to the original, the same basic idea will be just fine.

    Stick with it,

    -Abone.
     
  14. 55chieftain
    Joined: May 29, 2007
    Posts: 2,186

    55chieftain
    Member

    I have a 55 Pontiac is still has the x frame and parts were badly rusted. I remade the x frame using 1/8 steel which was alot heaver gauge than x frame. I welded together an i beam with 2" wide top and bottom and 4" wide was what i needed for the height. The center could get tricky though figuring placement of the driveshaft to go thru. Maybe boxing the frame would be a better solutuon?
     
    AGELE55 likes this.
  15. AGELE55
    Joined: Jan 4, 2018
    Posts: 235

    AGELE55
    Member

    20191207_150351.jpg 20191207_150329.jpg 20191207_150318.jpg Yep. Body is very straight. Minimal rust. I also have fenders,hood,headlight buckets, bumpers, etc. Not a bad find for $500.
     
  16. AGELE55
    Joined: Jan 4, 2018
    Posts: 235

    AGELE55
    Member

     
  17. AGELE55
    Joined: Jan 4, 2018
    Posts: 235

    AGELE55
    Member

    My coupe is a series 25 small body. Did you graft the TA parts onto a series 25 frame? Pics would be awesome..hint,hint..
     
  18. AGELE55
    Joined: Jan 4, 2018
    Posts: 235

    AGELE55
    Member

     
  19. AGELE55
    Joined: Jan 4, 2018
    Posts: 235

    AGELE55
    Member

    Lol...love that Poncho loyalty.
    Most everyone is saying I should mock up my drivetrain prior to modifying the frame which makes sense. Problem is I happen to have a SBC, but no Pontiac block to use. Is the 326 Pontiac and Chevy small block similar enough where I could use the SBC for mockup? Also, did Pontiac have unique transmissions or were they common with other GMs?
     
  20. abe lugo
    Joined: Nov 8, 2002
    Posts: 2,455

    abe lugo
    ALLIANCE MEMBER

    Don’t forget you have your VIN on the frame. In fact if you are changing the engine the VIN on the frame is the only way to ID it
     
  21. oldolds
    Joined: Oct 18, 2010
    Posts: 3,140

    oldolds
    Member

    That frame looks great, no rust thru and straight. I would clean up that frame to the standards you desire. Then box it and build a new x-member. When the frame is boxed the x-member will not have to be as heavy as the stock one was.
     
  22. bill gruendeman
    Joined: Jun 18, 2019
    Posts: 504

    bill gruendeman
    Member

    No My car is a 26 ( big body with 6 cyl ), I thought the small body like your take a Chevy frame ,shorter wheelbase and “tophat” frame rails. Check in the vin on yours I could wrong, it happens a lot lol.
     
  23. AGELE55
    Joined: Jan 4, 2018
    Posts: 235

    AGELE55
    Member

    My VIN is actually on the firewall.
     
  24. AGELE55
    Joined: Jan 4, 2018
    Posts: 235

    AGELE55
    Member

    I have been reading up on whatever I can find. The 39 Chevys were tophat frames. The Pontiacs were their own unique design.
     
    Lloyd's paint & glass likes this.
  25. Hnstray
    Joined: Aug 23, 2009
    Posts: 11,969

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Yes, you are correct, obviously. When GM shared basic body architecture across brand names, such as the GM 'A' body your car has, they generally used the chassis design, suspension and powertrains of the brand name they represented. For example, I have a 1941 Buick Special Sport Coupe, Series 40A. Most of the body shell is the same as Chevrolet, except where it matters.

    The chassis and power train is Buick but 118" wheelbase instead of the Series 40B 121" wb. The Series 40A cars comprised the coupe, convertible and formal roof four door sedan (same Chevy 'Fleetline' body shell, and no, not a fastback). and, although it uses the same grill and trim, fender style etc., the cowl of an 'A' body is about five inches narrower than the 'B' body. Lots of interesting stuff happened in the shared body shells across the lines.

    Ray
     
    AGELE55 likes this.
  26. oldtom69
    Joined: Dec 6, 2009
    Posts: 538

    oldtom69
    Member
    from grandin nd

    very nice body!worth fixing the frame for sure!
     
    AGELE55 likes this.
  27. goldmountain
    Joined: Jun 12, 2016
    Posts: 2,785

    goldmountain

    Canadian Pontiacs had Chevy drivetrain so stuff in a SBC and call it good.

    Sent from my SM-T350 using The H.A.M.B. mobile app
     
  28. AGELE55
    Joined: Jan 4, 2018
    Posts: 235

    AGELE55
    Member

    New question! What is the stock wheel size for the 39 Pontiac? I've got an opportunity to pick up a set of 15 x 7 Pontiac Rally II wheels pretty cheap. I think they would look kind of awesome on it.
     
    Truckdoctor Andy likes this.
  29. AGELE55
    Joined: Jan 4, 2018
    Posts: 235

    AGELE55
    Member

    So, where in SC are you? May be worth a road trip if you have a small block Pontiac... just saying
     
  30. Hnstray
    Joined: Aug 23, 2009
    Posts: 11,969

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    My reference manual says the tires were 6.00 x 16, no rim width given. However, I feel certain they would have been no wider than 5", if that, on the 25 series models. The wheel bolt pattern should have been 5 x 5" bolt circle.

    Ray
     

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