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Old 10-28-2023, 07:20 PM   #1
it2castelo
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71 C20 frame c-channel size?

My bumper was dented and bent pretty bad so I took off the hitch receiver and the bumper. To my dissatisfaction, the rear part of the frame looks like swiss cheese. The previous owners have drilled so many holes for different brackets there is barely any meat between all the holes.

Does anyone know the size of C20 frame c channel size? I measured it and cant really find any c channel or metal that is of similar size. I only need about 10 inches on each side. i cant really find a donor frame near me and I only need the last 10 inches of frame after the leaf spring perch brackets.
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Old 10-28-2023, 08:53 PM   #2
vardenafil
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Re: 71 C20 frame c-channel size?

https://www.classicchevy.com/1963-19...-884289-1.html

weld something like this on the frame to make it stronger? im in a similar situation as you. my frame is rusted/ damaged the last 10 inches or so.
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Old 10-29-2023, 12:32 AM   #3
Richard
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Re: 71 C20 frame c-channel size?

The rear part of my K10 frame tapers in height from the rear forward. Getting larger as it goes toward the front. Think all the frames are like this. Taller in the mid section. Can you cut out the side and weld in a new piece? The c-channel would require modification anyway. I extended my rear frame a few inches using plate steel. Was not that hard. Or, flatten the end of a piece of 3/4"-1" copper tube. Use it as backer, fill the holes in the frame with weld and grind smooth.
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Last edited by Richard; 10-29-2023 at 12:54 AM.
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Old 10-29-2023, 10:16 AM   #4
mr.mud1
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Re: 71 C20 frame c-channel size?

here's a few pictures of the tail end of the frame on my 72 C-20.It's hard to get in there with the spare in the way but holler if you need anymore pictures.the extra channel you see in the last 2 pictures are brackets for the aftermarket rear bumper.take care.Greg
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Old 10-29-2023, 11:34 AM   #5
1970cstblazer
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Lightbulb Re: 71 C20 frame c-channel size?

There should be someone on this board that is sectioning a parts frame that could easily and economically ship the relatively small sections required to properly repair your frame.

It's better to get original pieces. It will weld easier since the metal compositions and thickness should be identical or close to identical.
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Old 10-29-2023, 09:50 PM   #6
it2castelo
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Re: 71 C20 frame c-channel size?

Thanks for all the suggestions and ideas. I think I am just going to weld up and fill in all the holes.
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