Glen,
I think it would depend mostly on what you are going to use the Cobra for. If you are going to road race it go for one of the road race pans as they have baffles in them to keep the
oil from splashing away from the pickup. I use an Aviviad 8 quart one on mine but I raced it. If you aren't going to run the car hard and don't have enough clearance from the ground I would think that you could use any pan that fits a 289/302, even a stock one if it doesn't hang down to low. Just be sure to check the reading on your dipstick before you close it all up as you may have to make a new mark on it. When mine is full with the cooler and remote filter it takes 10 quarts and I had to mark my dipstick where the full was.
Ron