Rebuilding a Marine 318

I am currently rebuilding, actually tearing it down now, it is a low hours (miles) Chrysler Marine 318. I own a 25' Trojan Center Console Inboard boat that weighs about 3500 lbs. It is currently powerd by a very tired overheating (clogged block?) 318. I desire a very reliable, economical engine that will last a while. I have had 1/2 a dozen 318/360's in various Dodge truck and vans one of which went 250,000 miles and is still going for a local paint contractor. I have complete trust in the Mopar Marine engine. The block I have is clean and looks in good condition. It is original as it has never been broken open before to be rebuilt. I have a few questions and would like a little input from guys like MoparDan or anyone else very familiar with 318's

I have block # 2536030 then to the right of these #s 318 and what appears to be a 7. On the other side of the block is 12-73. Is this Dec of 1973 manufacture?

The heads are #2843675. Cast into the head close by is #2223 and AAWJ.

What heads and block do I have? Using my Mopar Small Block book I should have a 1970's (1973?) 318 combination. Am I correct?

I would like to use the same cast iron intake as I understand it is a Mopar Marine Intake designed for lowend torgue and midrange RPM's. Or would it be a Mopar RV/Truck intake? Will look up casting # on it soon.

I am wondering if I should find a set of 1.88"I 360 heads/308 heads/596 heads for it to breath a little easier. Is this a good Idea? Or should I look for a pair of mid 80's 318 heads? Or should I freshen these heads up?

I am planning on using the Mopar Performance Electronic Ignition Orange Box with a Hi energy coil. Good Idea?

I am planning on replacing the Carb (old AFB) with a  New/Reman Marine Edelbrock AFB (Carter AFB) in 625CFM with electric choke.

Not going to the expense of Roller valve train.

Any heads I get will have will get a fresh valve job.

NAPA is going to do the block prep and I will do final assembly. I've never done it before so this is all new to me. Rebuilt a bunch of Harleys, cracked cases/trannys so I'm reasonable sure its within my skillset (thanks Dad).

Cam will be the same Marine Grind currently installed as long as its servicable.

Rebuild kit will probably be a Speed-O-Motive Master Kit using only my rods, new pistons, rings bearings ect.

So...any words of wisdom for me?

Beach

Also...since I am putting new pistons in...why am I measuring Deck height NOW? Seems ot me this measurement is futile since the new pistons would then require a deck height measuremnet of their own?