[3drburb]

Originally Posted by davepl

I don't know if Grump is right - I assume he is - but my take on it is this:

GM didn't do anything that cost any money if it didn't have to be done. If it cost them 50 cents to drill those holes on a truck, that's half a million dollars some dude in jazzy suit didn't save them. That's a fat bonus in 1967 dollars! If only it worked that way...

But suffice to say GM didn't do a lot of unnecessary steps, and if they did, they often economized them out of the process by the end of a model run.

So, if you see it on all 5 years of our trucks, it's probably required.

If you see it in the 67s but not the 72s, it's probably a good idea.

If you see it in the 72s and not the 67s, it's something they had to add during production and is therefore probably a very good idea.

Those are just my general guidelines. I assume these holes are there for a reason (condensation most likely).

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To Longbox: wear gloves!

I found these on my 78 GMC and wondered the same thing.