Not unusual for the paint to not stick as well to aluminum when compared to steel parts. Paint can be stripped off when the parts were cleaned during a water pump or timing chain replacement at a shop or if the engine has been power washed at the coin self car washes as many of us can attest to. There are even a couple of period pictures of fairly new 65's but since it is so contrary to all the original engines and pictures we have access to this one or two examples (especially since they were magazine cars) its been accepted by most that the water pump and or housing had been removed or replaced for some reason.
Just wanted to mention before one of those two pictures get posted
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fmr187 - Good question and thanks for bring it up since sure others have seen the same pictures and may have assumed the same
Might I suggest pictures from the era posted in
The Assembly Line - Section under the Sub-Assembly & Supply Plants Sub-section
64 Cleveland Engine Plant V8 Oil Pressure Test
Early Small Block Product Test PicturesHope this helps
