I don't know what You have done so far but a trip to Double Venoms shop will be worth while. He will give you specific fan types and directions for their use. Together with the right radiator and proper shrouding I think you will find your problem to be history. A fan puller setup will generally work better on cobras than a pusher setup and this eliminates the fan getting into the radiator too.
I personally think a
oil cooler is obsolete on cobras and at best a band aid fix to THIS problem. I opted instead for a heat exchanger setup similar to the setup sold by Gordon Levy racing in Arizona. ( another thread ) Use water/
antifreeze wetter, I am using Red Line but there are others that work just as well.
Another thing, use regular
antifreeze, not permanent Dextron as reported here on Club Cobra as this stuff could corrode certain engine parts. And use distilled water in the mix as salts in drinking water will coat your coolant system reducing its efficiency. I know this isn't popular here on this board but a copper radiator will work better that it's aluminum counterpart, though it will be heavier. Make sure you use a reservoir at the high point of your engine to get the air out, and for sure run a thermostat.
In short, Go see Ed. He's been around the block a few times on this one.
cobrashock