engine replacement

the engine designer decided the rotation and the boat manufacturer decided what to use for there application.

count the number of bolts used to attached the intakes and if they match then move forward using the orginal crank, cam, dist, water pump, starter, alternator and transmission of the cracked engine block

In your case it doesn't matter on the rotation since your swaping everything out and you should be good to go. If worst comes to worst you should be able to use the old heads and not worry about the bolt pattern, just count the bolts on the intake of the FI and if they are the same number on your current application it will bolt up. On some they use 12 bolts and others they use 16.

I'm a little confused by your question. Are you planning to put the injected 351 in your '79? If so you have more to worry about than intake (i.e. rotation of engine). What exactly are your plans? Is this an automotive 351W?

To answer your question, yes, I believe the intakes will bolt up. But there are a lot of other issues. Any fuel injected 351W that I'm aware of will be LH (std.) rotation. Your '79 SN had a RH (rev.) rotation engine. You can switch rotations by getting a new prop and changing the orientation of the pump cover in the transmission. If you are converting an automotive engine make sure all of your electrical components are marine grade (i.e. starter, alternator, distributor). If not you're leaving yourself open to fire or explosion.