Engine Block cracked. Need Help

I assume you're asking about the block and heads specifically, not the entire engine.

You're engine is reverse rotation (RH-spins clockwise when standing behind the engine looking forward) because of this your cam, crank, distributor gear, starter rear main seal and front cover seal are RH specific. An automotive engine spinst in the opposite direction (LH)

With that said I am 99% sure you could use a standard automotive block and head. A few things to be careful of. With the head either buy a set or make sure the new head has the same specs has the old head (i.e. valve size and combustion chamber geometry) or your performance will be different on each bank. Additionally you may need to plug the ports in the head for emissions controls on automotive heads. As for the block, a standard block should work but you'll want to make sure all of the engine mounts and accessory mounts line up. I'm not sure if these were ever changed over the years or not.

a standard automotive block will work. Just switch over all the internals off your engine.

Ford 351's had many small changes over the years. Your safest option is to match block casting numbers to assure compatibility. The block casting number is located on the lower portion of the block under where the starter mounts. The casting number is virtually impossible to see when the engine is in the boat boat is easy to find if you put the engine on a stand and rotate it upside down.

Match head castings as well to ensure compatibility.

If you are not a mechanic take your current engine and new block to a reliable rebuilder. they will be able to reassemble new engine and let you know what if any parts need replaced or machine work needs to be done. Just make sure they don't try to talk you into too many "hot rod" performance upgrades. They may help performance, but will drive up your cost.

Surf some of the mustang and ford performance websites and discussion boards. They will have a lot more specific engine information about rebuilds, parts interchangeablilty, etc. Just remember to them high rpm horsepower is the goal. Your goal is probably a reliable engine so you can ski this summer.

Beware, just because that engine in Texas is marine, doesn't mean its the correct rotation for you.

Marine applications should not be your first rebuild. Buy an old F150 to tow your boat and rebuild/learn on that one. Like cshire said, just bring it to a competent machine shop that assembles engines for a living...the marine application is only a small step for those guy's. I worked with a pretty small Speed Shop and was surprised to hear that they average one marine reverse rotation bore/rebuild per year and knew all the ins and outs.

Shipping engines back and forth costs more than assembling one and must also be a factor in the decision.

Good Luck,