Projects 39 Pontiac Coupe (series 25 small body) build

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?
Gotta start somewhere... Thanks

 

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.

 

I'm in the Jacksonville Florida area. Looks like you're in NH, so not thinking you can mail it...lol

 

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??

 

Yeah, probably not very cost effective!

 

Mock up what ever power train you end up with then jus reinforce as needed. It is just like stating with a couple rails.

 

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.

 

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.

 

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

 

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

 

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.

 

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.

 

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?

 

Yep. Body is very straight. Minimal rust. I also have fenders,hood,headlight buckets, bumpers, etc. Not a bad find for $500.

 

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..

 

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?

 

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

 

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.

 

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.

 

My VIN is actually on the firewall.

 

I have been reading up on whatever I can find. The 39 Chevys were tophat frames. The Pontiacs were their own unique design.

 

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

 

very nice body!worth fixing the frame for sure!

 

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

 

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.

 

So, where in SC are you? May be worth a road trip if you have a small block Pontiac... just saying

 

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