If the alluminum is clean then 3 coats of gloss clear engine paint. If alluminum is discolored then 2 coats of gloss aluminum color engine paint and 2 coat of gloss clear engine paint. Thats what i hve done with boats and snowmobile engines.

One more question... Why wouldn't I want to install a closed cooling system? With that you no longer have to use marine parts etc on certain parts of the engine right?

closed cooling is handy, but you still have exhaust "rot" to deal with, and heat exchanger maintenance.

I ended up just buying a cast iron marine manifold. I'll stay stock until fall when I'm not trying to get back up and running quickly. As far as closed cooling, I'm alright with exhaust maintenance. It's the block etc that I'd like to keep away from the salt water.

Did you end up getting the GM one from my link ? 98% sure same one as from Mercruiser. Make that 99.5% sure as that is the only reason GM still makes it. Ie: for the marine world.

I think you're right that they're the same. I didn't get it from Pace though only because there's no mention of marine application and the shipping was $50. It cost about $40 more, but I went with eBasic power. I needed to order a few more things. The combined shipping made it cheaper.

Okay. Good.
I checked and same as the GM Intake.

I think they even used the same picture in their listings.

I'm a fan of closed cooling, too.
Your block has already seen a lot of salt, though. You'll want to flush it several times before you do your antifreeze fill.

You'll need to decide several things..
Do you want the oil cooler, power steering cooler to be on the antifreeze loop or the saltwater loop? That will affect the size of your heat exchanger. Mercruiser runs the lower exhaust manifolds in the antifreeze loop which brings the engine up to proper teml quicker and increases exhaust manifold life but also increases the size of the heat exchanger. You'll need to decide if thats what you want to do as well. Do you plan to stay under 350hp or do you want to see 425hp? That will affect the size of your heat exchanger..
How accessible is your existing seawater pump? If you can reach it easily for impeller changes, then great. If not, youll want to relocate it or get a crankshaft mounted pump to save your body from punctures and lacerations doing impeller service.

Running antifreeze thru the exhaust nanifolds (the lower part) will require a Mercruiser closed cooling thermostat housing, and block off plates between the exh mans and the exhaust elbows to keep antifreeze from flowing into the elbows.

If you run saltwater thru the exhaust manifolds, you use an automotive thermostat housing and run standard elbow gaskets.

350hp heat exchangers are relatively compact but you still have to put em somewhere. Look at your options and keep in mind that you will need access to the distributor, throttle and shift cables, access to the steering cable and steering ram if you put the exchanger on the rear of the motor. And if you put it near the front, you'll need belt and pump access, etc.

Great info. Thanks. I'm going to have to get a little more edjumacated on all my systems before I decide. I plan on staying pretty close to stock because it's a cruiser. I'd definitely want to have everything possible that's salt water cooled changed to closed cooling. Yes, alot of flushing will need to take place first....