I ordered a Milodon 7 quart oil pan for a 383 stroker. In the box was a non-stroker clearanced oil pan. It had not appeared that the box had been opened before. The next morning, next day air, I received a second one which was clearanced. Summit's customer service is second to no one.
Maybe yours came clearanced for a stroker, and you did not know it.
This blown 383's total fill, with the oil filter is 7 quarts. So the oil pan only has 6 quarts in it at the full mark on the dip stick. The oil does not cavitate, and I have not seen any oil consumption since replacing the cheap/leaky oil pan that was on it a year ago.