67-72 frame side cab mount bracket differences?

[CC69Rat]

I have a 67 SWB about to go to paint. Dad and I have already cleaned, and detailed the chassis, and I am really trying keep it that way.

So, a couple weeks ago I found another 67-72 SWB chassis. Talked to the wife, fast forward .. 4.5Hr drive, in the pouring rain to go get it.

We get there, I knew it was a 67-72 chassis. It hadnt been cut down, the frame horns matched up, 69 VIN stamp. (9Pxxxxxx) Pretty decent chassis. 69 narrow 6 lug housing, HA stamp (3:73) Non posi.

But -- it needed some love. Somebody at some point in it's life had knocked the cab mounts, the bed mount / stand things and the core support mount brackets off of the frame rails. It is just bare. I asked him about it, and he said it had a 50s model cab on it when he got it. It hadnt been hacked on, and I just needed a roller frame. I want an Auto Cross C10 anyway .. So, .. Hum? Maaayybe ?? After the 67 gets back from paint, I see a race truck in my life? It would be a good frame to convert to Hotchkis / Ridetech kit at some point.

He told me he had another LWB frame too, but someone had cut it in half with a plasma cutter. If I wanted the SWB chassis, he would give me the LWB frame, just to get the brackets off of it. I'll just bolt them back on the SWB frame, and go with it.

Here lies the issue..

The brackets arent lining up with the bolt holes where the original C10 Frame side cab mount brackets were. You could still tell where they were originally, the old rivet heads were still in the frame.

The frame holes are wider than the brackets I have worked for 4 days to get off the LWB frame pieces he gave me.

??? I thought they were all the same? The LWB frame has a trailing arm cross member in it..

If you measure across the bottom rivet holes of the front cab mount bracket I took off the LWB frame, it is 4 11/16" center to center.

The holes in the 69 SWB frame where it is supposed to go are 5 1/4" center to center ?

But, measuring my 67 chassis -- they are 4 11/16" !


The rear cab mount brackets arent working either. The frame holes are too wide for the bracket spacing. Same deal, 5 1/4" spacing between the holes

Are the cab mount brackets wider in 69-72? The top two holes in the front cab mount bracket line up fine.


If there is anyone out there with a 69-72 frame, that wouldnt mind measuring this for me I would really appreciate it. I just need to know if the lower two rivet holes in the front cab mount are 4 11/16" center to center? Or are they closer to 5 1/4"?

I cant figure it out.
Thanks.

[HalfBrit]

The rivet spacing on my '70 is right at 5 1/4"

[CC69Rat]

Thank you for measuring ! Just curious if yours is a C10 2wd ?

Just trying to figure out why some seem to be different than others?

[HalfBrit]

Yes it is. A 307 / 3 speed base trim truck. The assembly manual might reference the differences, if there are any. I'll look, when I get a minute

[CC69Rat]

Ok, one more question ? Just trying to find the variable between one style of mount vs the other. Why is your frame, and this 69 frame wider? I think I may have found it.

If you follow the edge of your front cab mounts, are they straight down the sides, or curved?

Thanks again for your help!

[CC69Rat]

Got it figured out.

The 63-66 style cab mounts are narrower than the 67-72 style.

My 67 Chassis is a very early build 67 Small back window.
So, I am betting my 67 truck is sitting on and / or sharing some of the 66 leftover parts. I am thinking maybe it has the 66 style cab mounts on it.

The LWB frame the guy gave me .. ? It is also 63-66. So, of course the cab mounts were matching up when I measured them.

I was just using my 67 Chassis as the 'source of truth' because I felt like it hadnt been messed with. When in reality, it has the 66 mounts on it.

So -- 67-72 cab mounts are different. My 69 roller chassis needs those mounts instead. The extra brackets off the LWB scrap frame werent correct to begin with... BUT they matched my 67 frame, so I thought they would be. NOPE.. Lesson learned.

67-72 cab mount set is on the way.
Thanks for your help getting it worked out.

[HalfBrit]

Nice detective work! Just when you think you've seen all of the assembly line quirks, Chevy throws another curve ball, lol.