Factors that brought this into play were the Great Depression that resulted in fewer sales and lesser income as well as the shift to all-steel bodies that required more expensive production tooling.
Platforms were designated by letter. The link above states:
"Harley Earl showed Kaptur's conclusions to Fished Body and suggested that all GM cars share four basic body shells. He designeted these A-B-C-D. The A-body would be used by Chevrolet, standard Pontiac and small Oldsmobile. The large Pontiac, mid-size Oldsmobile and small Buick would use the B shell. The C-body accommodated the big Olds, big Buick, LaSalle and small Cadillac. And all Cadillac and Buick limousines used the D body."
That was the concept, but details varied over time.
Wikipedia has entries dealing with the bodies dealt with in this post: A platform here; B platform here; C platform here. At this time I drafted this (February 2024), some details did not agree with Lamm and Holls, who I am more inclined to trust.
The problem is, aside from Chevrolets, the bodies of other GM cars look essentially the same regarding profiles, door and window shapes and such. That is, they seem to share most body tooling and sheet metal stamping. Therefore, body type is difficult to clearly identify, the information in the quote above not being helpful. I lack charts of body dimensions, so the analysis below is simply based on study of photos. More precise information is greatly appreciated.
Photos below are of cars listed for sale on the Internet.
This is the new A-body Chevy. 1934 Chevrolet Standards carried over 1934 bodies.
The main change for 1936 was replacing the forward "suicide" door with one hinged on the A-pillar. Note that the back of the passenger compartment drops nearly vertically.
About the same wheelbase as the Chevrolet Master DeLuxe, but with a different aft profile. Might this be a B-body? Wikipedia says this is an A body.
Another example of a possible 1935 B-body 4-door sedan, though Wikipedia has this as an A. Front doors hinge on the B-pillar, sharing the shape seen on the 1935 Chevy in the top image. The new "Turret Top" (without a fabric insert) had its shape dictated by body engineers more than stylists who echoed the roof curvature in the window shapes.
The larger Olds Eight, with what seems to a C-body -- or B, according to Wikipedia. Quite similar to the Olds in the previous image, but note the top hinge on the C-pillar is mounted higher.
Buicks did not get the new bodies until the 1936 model year. This seemingly is like the above Olds Eight -- a B, Wikipedia says. The hood is long to accommodate an inline eight cylinder motor.
According to the quote above, this LaSalle should be sporting a B-body, if Wikipedia is correct. That should confirm my guesses regarding the two cars shown above. But...
Wikipedia has this as a C-body. Yet it looks like the LaSalle -- which brand Wikipedia ignored in the links above.
Yes, plenty of guesswork here. Aside from Chevrolet, there's so much similarity that I wonder if 1935-36 B and C bodies were worth different labels.
Donald,
ReplyDeleteGreat analysis of early GM car body standardization. I agree that these early A, B, C, D bodies are sometimes hard to distinguish between the various platforms. Looking at the placement of door hinges is a good idea. I find the then-all-new 1937-1938 bodies have the same visual identification issues. I believe that the bodies were not actually classified as entire shells for one car of a given "body," but rather as 2 or 3 separate shells that could be mixed-and-matched as needed, with the various combinations used to denote the difference between a "standard-body" or "extended-body" of said body class. For example, Buick had multiple "B body" cars during this era, one was the smaller "Special" (Series 40), another was the slightly longer "Century" (Series 60) that had the large Straight-8 engine found in the largest "extended" B body Buick "Roadmaster" (Series 80). Interestingly, the Series 60 title was also used by Cadillac to denote their "small" B body offering (which was roughly the same size as the "extended" Buick series 60). The sense I get is that each "body" was broken down into 2 sections ("cabin" and "front clip") that allowed for the different engines to be offered in the different model "series" of each make using the "standard" cabin body stamping with only minor modifications necessary to elongate a given chassis to accept the larger engine (more pistons in an inline engine necessitated the longer front clip but not necessarily a larger cabin). Some models used a specially modified larger cabin with an extended chassis and front clip together simply for the sake of luxury (Cadillac Series 65 and Buick Series 70 "Roadmaster").
My breakdown:
D (Extended Special) - Cadillac Series 80, Series 85, Series 90 (extended Fleetwood D bodies with extended front clip)
D (Standard) - Cadillac Series 75, Buick Series 90 "Limited" (standard Fleetwood D bodies)
C (Standard) - Cadillac Series 70, Buick Series 80 "Limited (standard Fleetwood C bodies)
B (Extended Special) - Cadillac Series 65, Buick Series 70 "Roadmaster" (extended Fisher B bodies with Fisher built C body front clip)
B (Extended) - Cadillac Series 60, LaSalle Series 50, Buick Series 60 "Century" (standard Fisher B bodies with extended front clip)
B (Standard) - Buick Series 40 "Special," Oldsmobile L series (standard Fisher B bodies)
A (Extended) - Oldsmobile F series, Pontiac 8 series, Chevrolet "Master" (standard Fisher A bodies with extended front clip)
A (Standard) - Pontiac 6 series, Chevrolet "Standard" (standard Fisher A bodies)
Elias
Elias -- I greatly appreciate your comment with that analysis. I too wondered whether some body bits carried across platform categories, given similarities. (Might that negate the concept of platform or body type? My post regarding the 1950-ish B-body, C-body situation touches on this, though that might well have been changing GM in-house labeling.)
ReplyDeleteMaybe it's my #&^%*@ academic background, but I thought that I really needed something solid: documentation on the matter. But since I'm not writing a book on the subject, I wasn't going to tap GM archives. Plus, all GM body engineering employees from that era are long past being interviewed. I suppose there might be shop manuals or some such information regarding framing and stamping for cross-brand comparisons. Or maybe some restoration shops might know what was what.
That said, your conjectural list seems very useful -- I just screen-saved it for reference. Much better than all the notes I wrote to myself last January when I spent several weeks flitting from photo to photo trying to identify which body was which.
Many thanks for your effort.