For what it's worth, the factory mopar oil coolers were mounted in front of the radiator, at about center-block level. They are fed from the upper oil gallery, and where it came out of the block, there's a factory mopar checkvalve for anti-drain back. As long as you do something like that, you're at least as good as factory.

If you want that part number, I can get it for you. can probably still find them. I'm sure they are around as typical race parts, too.