I do not recall seeing a dipstick mounted like that. I would ask the prior owner about it, but if he was saying that
oil fills could be anywhere from 8-12 quarts, I am not sure that he knows much. How much
oil do you think that you removed?
If it is not too difficult, I would consider removing the pan to take a look and see what you have there. While you are down there, you might want to take a look at the
oil cooler lines to make sure they are routed correctly. the oil should go from the block to the filter, then to the oil cooler and back to the block.
How many miles on the car and how many have you put on it since purchasing it? There are a lot of knowledgable cobra people in AZ that should be able to visit and take a look at things for you.