I could see the need for a full system in a cruiser style boat where access is limited to the manifolds. In a performance application where the boat is on a trailer , a half system is sufficient. A 10 minute flush with saltaway cleans out the coolers and the exhaust.

I'm curious if anyone has done testing with the standard engine water pump vs a high flow unit such as flowkooler makes in a closed cooled system? Not the seawater pump, I'm talking about the pump that will have the glycol going through it.

I'm not sure if it would do anything or not? Maybe make it worse? who knows?

A high flow pump can only help. Anything to increase flow velocity and get to a Reynolds number of an RE>3500 and try to maintain an RE>4000 to get to or maintain turbulent is a good thing when cooling.

Hi Bud, Can you explain all those RE numbers. Haven't heard that one before

It's a calculation used to distinguish between laminar and turbulent flow of a fluid depending on it's viscosity. Usually for pipes and what size to used for efficient cooling. I'm loosely using it in cooling terms of an engine block. Laminar flow is when you turn your faucet on slowly and it smoothly comes out of the faucet. Then you get to the point where all he// breaks loose and it's not a nice stream. There you have turbulence and better cooling.
https://resources.system-analysis.ca...turbulent-flow

Jas can you give me the length & square end measurement to your dd15?........I found one 20"-5/16's long by 3" x 3" square at the ends.
or give me what capacity a DD15 cooler cooler would work for a N/A 572 cu. in. BBC 700hp?

It's about 750mm long and 4" X 4 1/2" in size. But that will do 1200hp, so your smaller one will be plenty for 700na easily...but count how many tubes and how long and call a heat exchanger guy and ask him if its enough... Or compare with a commerical available one... Jas

So your exchanger (cooler) 750mm (almost 30") can you tell me how many tubes yours contains?....it will give me an idea relative to my engine hp

Here is the picture with the tails installed... I am installing the cooler beside the engine, if you have it in front of the engine, your tails will be quite different... Jas

Jas .....Appears you can fabricate (nice job) I don't think that would be the same for me...Buying a used Detroit dd15 cooler is a cheap first step especially if you can do all the fabrication yourself
but in my case, having someone else to (a fab shop) do all the work would probably go over the cost effectiveness of it .....I love the idea in principle that the dd15 has a much better cooling capacity
then a mfr. marine closed cooling system (shell & tube) but just wondering where this would end up for me if I get my feet wet.........post up (pic) as you get to completion, seems it's going in the right
direction.