Difference between one piece and two piece X frame?

1964SuperStocker

Well Known Member
Supporting Member 3
Picked up a full size Chevy X frame today and noticed it had a frame slightly different construction then on 2 of my cars. Did they have an early vs Late style X frame and which came first the one piece or the Two piece? Very interesting because I never knew there was any difference between the actual X frames like this.
 

oldskydog

Well Known Member
Supporting Member 10
Look in the Assembly Manual. It should show two different part numbers for the frame as optional use on the assembly line depending on which supplier stocks that plant at any given time..could be that both are used interchangeably. I know that is true of 55-57 and am assuming it was also true for later years.
 

4speedman

Well Known Member
Supporting Member 2
I have had one of each kind out for a frame off and the 40 pounds difference is about right.
 

rstreet

Well Known Member
Supporting Member 17
When you refer to a one piece and a two piece frame do you mean the 61 boxed frame verses the channel frame? I'm not aware of a two piece frame. What did i miss?

I don’t think you missed. I always thought two different builders and the significant difference was “C” verses boxed. Then both frames were stiffened for convertible use. I’d bet there were several weight differences depending on the body that was on them!
The majority of us on the site are two door folks so the differences are much fewer possible combinations.
I have rolled from underneath my 61 and 62 coupes and by eye can’t tell any real difference but I have always suspected a difference. Maybe Cecil has a different part number and design drawing between 61&62.
My 61 convertible is boxed and reinforced so that style has got to be at the top of the weight difference I would suspect
Robert
 

1958 delivery

Well Known Member
Supporting Member 2
Easy to spot. 2 piece has two C channels welded together with big globs of weld every foot or so. The 1 piece is a clean "boxed" type, there is a very slight weld bead running the length of the frame rails which is hardly noticeably most of the time, looks more like an electric(arc) type weld bead.
 

oldskydog

Well Known Member
Supporting Member 10
OK guys, I thought I pointed this out in a previous post. Frame differences were due to different suppliers for all except L.D. and convert.

From 61 AIM:

FRAME ASM.
3786623 All except convertible-L.D.
3786625 Opt.
3786627 Opt.
3777098 R. D.
3777099 Convertible
 

quik9r

Well Known Member
Supporting Member 3
I like"wrinkle frame" Seems most one piece came from Baltimore or Flint plants. I climb under everyone and always ask to open door and find out assembly plant. Just my thing
 

ragtp66

Well Known Member
There were three manufactures of frames. The A.O Smith built frames were the open 1piece "C" channel frames. The 2piece welded c channel frame with a welded visible seam was made by Budd, and the one piece "seameless" frame was made by Chevrolet. Three different suppliers. I won't get into the California/Canadian frame debate but those are the differences in the three types of frames.
 

rstreet

Well Known Member
Supporting Member 17
I like"wrinkle frame" Seems most one piece came from Baltimore or Flint plants. I climb under everyone and always ask to open door and find out assembly plant. Just my thing
My 61’s and 62 were all St Louis builds so maybe they were starched and ironed:D actually the reinforced strip on the convertible looks like an apprentice first week on the job.
Robert
 

real61ss

Well Known Member
Supporting Member 8
Tom,
But that is a picture of the front horns, I've never a 61 frame that didnt look like that in the front. The rear is where ive noticed the big difference. The white 61 SS that I owned had the square tubing behind the rear axle, prettist thing Ive seen as there no welds. I wish i had a photo of it, at first i thought it was becase the car was a Super Sport but i quickly learned that the fact that it was an SS had nothing to do it when i saw a 4 door hardtop with the same frame. I think those two cars may be the only tube frame cars ive seen. The blue SS that Robert has now has has the C frame. Great discussion. BTW, the two cars that i have seen with the square tube frames were Atlanta built cars
 
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