I would like photos of original 65-67 442 radiator caps if anyone has some. The numbers I have are as follows:
65- gm 861042
66- gm 3887586
67- gm 861042
I don't know if these numbers are correct or not; but thats what I got from some 65-67 AIM's. Seems odd they would change in 66 then change back in 67.

68-70- gm 6410366

Here are some photos that might be correct. Take a look. Maybe you know what these are from?

 

The 861042 is the only radiator cap listed for Olds from 61-67. It is superseded by 861050. Both are 15# caps. There is no mention of W29 caps vs std V8 or V6. The parts catalog lists this one cap for ALL 61-67s. The difference on the 65 442 would have been the identification number on the upper tank. This number and letter combo varied based on manual vs auto vs A/C car.

 

66 AIM has different number. Those numbers look like they are from parts book. Thanks