Maybe Mr Cool didn’t have a full kit? I chatted with Russ from Mr Cool and he had no problem recommending the right direction to go with his line for my 509s. I didn’t quite go in his direction, but if I find the 454/502 heat exchangers are overwhelmed in warmer water, I’ll make adjustments from his suggestions.

The CP Performance kit that seafordguy used on the tall-decks in his Tiger would definitely do the job for you. About $2k each I think.

Maybe so, but I told him (Brandon) I wanted a fully closed system and he didn't offer too much.......What he was interested in was the topic of the DD15 exchangers. I sent him pics of ecuchips fabrication DD15 exchanger for his perf. race boat.
For comparative size (he said) ...a typical Marine big shell and tube system is far inferior to a much smaller detroit diesel exchangers cooling capacity.......point taken, but the DD15 is not a designed (ready made kit) for boats and getting it there
would require much fabrication....... There's a used Merc 454/502 Exchanger on ebay $975 salt water used - too small & too expensive for a saltine.

Okay. I got it now… full closed cooling. I guess I missed that somewhere. That’s going to be much harder to do with any performance big block.

I’m only doing the blocks. Exhaust was never a consideration.

Interesting about the conversation around the Detroit cooler. Maybe a new product idea for them?

Tom that's just what I thought also....He sent all the pics of the fabricated dd15 conversion to his design shop.

Jas, I've got B&M 420s I need to setup with heat exchangers. I have the massive thermostat housing extension (alum) that has a big cast iron housing and outlet to the manifolds.

I really really like how you pull coolant out of the intake to the exchanger.
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​​​​The thermostat is under the black intake manifold connector?

Do you have a water circulation system for when the thermostat is closed?

Just seeing that unique CC system that's fabricated to fit in a small space ....for a blower race engine?....real credit to the designer & fabricator!

Totally...this is the type of revolutionary stuff that was happening in the early days of hotrodding. Re-purposing quality parts with some mods.

For minimal outlay, I can make fully cooled system and keep my Stainless Marine manifolds fresh for a lot longer. Vs a multi-metal exhanger that would likely cost $3500 USD for just 2 exchangers sufficient for 650-700 HP full system.

I'm also excited to get rid of the heavy extended coolant fittings that came with my 420s. Bonus. Less parts...less seals...gtg.

Those pictures alone are worth a thousand words!...my first & only intentions were to rid the corrosion from ocean salt on expensive engine components ( 2 Imco manifolds, risers, coolers) ets; etc; ~ takes a $$ toll.
Plus the benefit for a consistent engine cooling adds so much more attractiveness in this CC system........I'd love to replicate what Jas did and apply it to my engines .....again, the idea to close cool 1100 hp with
smaller & far superior system is enough said......I have to just jump in & find (2) - DD15's ....and not worry about the next step.

There used available that are cleaned and pressure tested.

Even if they are tested...you need to test them before you start the mods...or you could end up chasing an issue that is not your welds.

Yes I agree!.....generally speaking, would you know where to shop for a good condition "used" DD 15 EGR Cooler?.....