First off, where are the pics of the regal lol! In regards to the oil pan, you need to determine whether the SBC you plan on using is driver or passenger side dipstick. You must have a rear sump so that the pan clears the front crossmember. If memory serves me right, most pre '86 blocks should be driver side dipstick so that pan might work, the sump might hang too low.
You also need to make sure the oil pump used works well with the pan, and the pump pickup is spaced close enough to ensure you have no oil supply issues. Personally, i would recommend getting an oil pump w/ pickup tube and oil pan from the same vehicle if youfind a donor.
Hope this helps man, im sure others will chime in and add on if i missed anything.