Hey Gang,
I'm putting together a 26' LS Scarab with a very clean stock 502 EFI with 200 hours (harvested from a Cobalt that lived it's life on Lake Tahoe and has never seen salt) I am moving to Florida and will be running it mainly on the inner coastal waterways - I'd like to protect the motor as much as possible from internal 'rot' and would like input on a 1/2 or full closed cooling system. The motor will have CMI e-tops through hull exhaust.
Thanks in advance!!

Half , or 'partial' FWC is probably the most common because in a 'full FWC' system the heat exchanger is larger and the plumbing is a bit more complex as they cover the exhaust manifold (but not the riser) as well .
IMO it's worth every penny . Bear in mind that the 502 comes with dissimilar materials like an alloy intake manifold and stainless recirc pump so once you put that fresh water anti freeze mix in you're good to go for a long time.

Possibly the best money I have ever spent. Do it..... I used the CP Performance kit.

On a side note, one of the worst things about salt water is the trailer. My twenty year old trailer looked and worked like new until just a couple dunks into salt water. Just one of those considerations for #saltlife.

Thanks for the quick response and info I really appreciate the "brain trust" of knowledge! Yup its sitting on an aluminum I-beam heavy duty tandem trailer👍🏁🇺🇸

I honestly don’t know why boats don’t come with at least partial closed cooling from the factory. I don’t see any legit downside to it.

$$$

Monitor in brooksville fl makes a great system … I have a carbed 540 now but it started as a gen 6 502 mag mpi. I have a lot more power now but the system is working great.

Nice set up Is that OEM Mercruiser or aftermarket?

steel trailer?