Bear in mind too that all the Marine 427's were center oiler engines. They were in fact cast in side oiler molds and they have all of the side oiler bosses, but none are drilled. They all also had the screw in brass freeze plugs too. This is true of every one that I have ever seen, and that was quite a few. I ran a machine shop on the Chesapeake Bay for 16 years. The reverse rotation engine block is no difference...the only thing I remember, other than the obvious was that the crankshaft rear main seal surface had those little slanted cuts to push the
oil away slanted the other way. We used to grind them smooth on the crank grinder and use the crank anyway...which, by the way, are not steel. Every one of them I saw was always just a cast iron crank, same as a 390. The connecting rods are 390 type, sorry, not the Lemans rods...Bottom line, if you get them both, it's not as if you have one complete engine that is useless, you aren't going to use the camshaft and distributor anyways. Pistons were the same just put on the rods 180 out. I have actually seen the crankshafts used without removing the little slants and it didn't leak
oil. I don't recall ever seeing any of these motors that were fresh water cooled with heat exchangers. They were all raw water cooled {salt water} but because of the higher nickle content typically not ate right up like other plain cast iron blocks. The cylinder heads are just 390's too. Best of luck, just don't pay or expect side oiler prices.....M