I am going to add a heat exchanger to cool the block as well as the oil/power steering cooler. My question is can I just add another raw water pump to circulate the closed antifreeze loop, or do I have to add a regular water pump to the engine (588cu / 700hp)? Motor looks nice with crossover and it would be a shame to clutter it up with a block water pump. Directions say you need to push 100gal per min on the closed side.

I'm doing the same thing, with 572/700, and just received my aluminum water pump to replace my crossover - had the same concern, and didn't want to do it either, but couldn't imagine another way to do it - I sure don't want another raw water pump and more hose cluttering things up.... Even a crank direct driven raw water pump would still mean more hoses, fittings and hose clamps than a regular circulating pump. The good news is that I don't see any reason to do a "marine" grade (more $$) circulation pump since it wont be running raw water. I'm going to paint it before it goes on the motor, so the backside is painted well since I'm in brackish/salt water.... I also figure my new tunnel ram and dual carbs setup, all nicely painted, will keep anyone from noticing whether I have a crossover or a water pump, lol

What bothers me more is that I'm adding complexity to the engine "system:... hate it, but no choice after spending the time and $$ on alumn heads...

Must have circ pump in closed cooling. Can't run crossover.

As always, thanks guys

so you want to route the raw water like this:

into boat - sea pump - heat exchanger (water side) - exhaust- overboard,

and you want your 50/50 circulating thru

heat exchanger (coolant side)- engine block- engine oil cooler - power steering cooler.

or am i reading your post wrong.

He was wondering if possible to run raw pump for a circ pump. I am sure with a little butchery it is thoeretically possible, but rubber vanes really prefer cold to hot water.

dereknkathy got it right. I wanted to use a second raw pump (not pumping outside salt water) as a circulating pump, this way I could put the second pump off to the side and not clutter the engine.

oh !
what about electric

[ATTACH=CONFIG]566874[/ATTACH]

you have to buy these parts anyway so it's just a matter of configuration to try and keep the engine uncluttered
anything can be done,

edit in assembly, so the heat exchanger, electric circ pump and crossover would have to be an off engine assembly
mounted to a stringer bulk head or firewall,

I would cool the p/s,oil cooler with raw water not the closed cooling..