The rear
oil grooves on the reverse rotation crank are backwards. Other than that it's the same as a std rotation crank. Either they can be smoothed or some guys just run them with a neoprene seal but why chance a rear main leak. You can just install a std rotation FE crank. Either way it's a basic 390 internals for the 427 marine. The cam also is reverse rotation but only on the reverse engine. Figure at best your spending $1500 on just the block. I looked at one of these a few years back and the price was the same. It was fresh water cooled but raced it's whole life and pretty spent! However the marine blocks are pretty good if not to corrorded and or cracked. Take the above advise given and let someone look at it with you. Good luck, G.