First be sure your
oil pickup on the
oil pump is matched to the pan, picking up
oil from the deepest part of the sump (front or rear as the case may be). Then check what the pan manufacturer says is the pan capacity. I was getting ready to fill my "T" pan with oil for the first time and wondered how much, then saw the manufacturer calls it a seven quart pan (eight with filter). Oil came right up to the full mark on the dipstick. (I realize you may not have fitted dipstick yet).