All production 351W motors are 2 bolt. Pretty sure even the FRP Sportsman blocks are 2 bolt. The aftermarket SVO, and Dart blocks are 4 bolt. The 351W production blocks can be converted to 4 bolt. Believe Moroso or Milodon make 4 bolt center caps that can be installed, but haven't seen this as a popular option.
For Mustang use, a 7 qt pan should be fine. For Cobra use, get the baffled 8 qt (Moroso/Milodon), or 9 qt Canton. The acceleration, braking, and cornering of even a street Cobra throws the
oil all over the pan and can easily uncover the
oil pickup in a stock, or near stock pan.
For Mustang use, particularly the heavier '69's to '73's, a 393 or 408 stroker would make for a torquier engine.