39 vs 40 Frame Differences

Pech33

Pech33

Senior Member
I have a line on a 39 frame for my 40 convertible. Any noticeable issues in using the 39 under my car? I know the closed car frames for 40 were of 10 gauge steel, while the open cars were 11 gauge, what about the 39?

Was the suspension the same, tie rods, shocks, front and rear axles etc? I believe the center bracket (with the x on it) is slightly different on the 39.
 
Right you are, 10 is thicker than 11. Kube says, on page 4-7 of his book, that closed cars have .100” thick frame rails and open cars have .110 thick frame rails. It does not make sense to me either, but that’s what it says.
 
Doesn’t make sense in that an open car doesn’t have the rigidity of a one piece steel body connected together with a steel top. Henry must of had a method to his madness, I just don’t know what the reasoning was. Weight?
 
The commercial half-ton frame also has a guage thicker outer rail. There are two front crossmembers in '39-std /deluxe. And the open cars have a cowl brace member in the front section[easy replaced.] Still the '39 frame can be made to work. Newc
 
Pech33 said:
Right you are, 10 is thicker than 11. Kube says, on page 4-7 of his book, that closed cars have .100” thick frame rails and open cars have .110 thick frame rails. It does not make sense to me either, but that’s what it says.
Click to expand...

Why doesn't that make sense? The open car frame rails are thicker = stronger.
 
Pech33 said:
I have a line on a 39 frame for my 40 convertible. Any noticeable issues in using the 39 under my car? I know the closed car frames for 40 were of 10 gauge steel, while the open cars were 11 gauge, what about the 39?

Was the suspension the same, tie rods, shocks, front and rear axles etc? I believe the center bracket (with the x on it) is slightly different on the 39.
Click to expand...

For what you are attempting to accomplish, the frame you have your sights on will work fine.
Transfer the supports that are on the '40 frame - the ones just behind the dash panel They are bolted in so are easy to transfer to the donor frame. I have added a photo of the brackets.
Depending on when the 39 frame was manufactured, it may not have the holes in the front frame horns for the sway bar brackets. easy enough to figure out where they go from your rusted (current) frame.
That's it... everything else will bolt in directly.

As has been mentioned in a previous post, if the '39 frame is from a standard, the front crossmember must be replaced with a '39 deluxe or '40 member.
 

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I know you guys know this but I will mention that if it is a 39 standard frame the radiator mounts will have to be changed also.
 
So, after you put the '39 frame under the '40 how do you handle the serial # issue? I suppose you can cut the number off the '40 frame with a zip cutter and fit and weld it in the right place, grind the evidence, paint it and Bobs yer uncle. Am I overthinking this? Bill
 
0.110 inch is not 11 gauge, 0.100 is not 10 gauge. It’s quite the opposite. The smaller the number the thicker the object. 10 gauge sheet steel just happens to be 0.110 and 11 gauge 0.100
 
Just did this. The '39 X will not have the "bump-out" where the '40 clutch pivot ball bracket bolts to. I had to graft that piece into my frame for the '40 clutch linkage.
 
I will get the serial number handled one of two ways, either cut it off and re-weld it to the new frame or restamp it. There is a member of this forum who has offered to lend me the correct stamps. I can put the frame on a trailer go down to Shelton, WA and stamp the serial number in the correct places on the frame. The number on the title is already wrong. It is missing one of the numbers. I don’t know if that was done in Iowa where the car was for many years or in Michigan where it was for four years. My Washington title can be corrected with a visit to the State Patrol, no thanks.
 
Pech33, You can also just borrow the stamps as you said. Much easier to transport then the frame! I will however do that for you if that is what you want to do. I have a friend who has a 40 that the VIN on his title is 91A-6049 which you may recognize is the part number of one of the heads! (they are 6049 and 6050) That car came from California.
 
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