Jim,

I went through the same exercise on my 41. 70+ years allows a lot of time for extraneous hole creation. I don't think that an oil filter was ever mounted on the drivers side firewall, but late 1941-45 military trucks all had an oil filter mounted on the passenger side of the firewall.

Are you certain the holes you mentioned are not for your voltage regulator? If you look really close at suspect holes (with a magnifying glass if necessary), you can see the difference between a factory stamped hole and a drilled hole.

Paul


1941 Chevy 1 1/2-ton WW2 4x4 dump truck
In the Stovebolt Gallery
Lots more pictures