I’m looking to achieve the most constant water temps throughout the engines.

Ive drilled and tapped the rear of intake and ran 8 AN from side to side with a T in the middle with a 4 or or 6 AN hose out the transom in the past. My goal has always been to dump the hotter water in the rear trying to achieve more consistent temps from front to rear as the rear is always hotter.

Question is it as equally important to run hoses from front to rear as well in addition to?

Looking for some opinions. Seems like Rookie showed some pics with different size restricters he made but can’t remember how all was plumbed.

Tks

What you are after is supposed to be one of the benefits of the 4/7 swap cams. I think you are on the right track track as you can count me in as one who has lost either 7 or 8 in a marine engine.

you want advice but dont say what the engine / exhaust configuration is

If using Mark IV blocks, read on difference (internet search) between parallel and series cooling for bbc (big block chevy)

I believe rookie had crossover system with bypass and using restrictor in the bypass section for proper block water psi ?? I’m just talking/thinking out loud....surely he’ll reply.

Seems as though you recall that same thread. Heck I probably started for all I know but searched and couldn’t find. Rather than the restrictors I had used a ball valve at the transom to regulate pressure.

Builds are dart big m 9.8 565’s. 740-750 NA. 6,300 rpm.

I will be running my x overs and bypass.

My thought if dumping the rear, - would it be non beneficial to run front to rear. Just thinking out loud.

Valako picked up my intakes while up deer hunting however they are the Brodix hv2001’s

Yes SB I finally bought them. Hah

I might suggest dumping both rears of the intake directly overboard with AN -8s all independent of each other, I did this on my engines it helps at sustained higher RPM runs.

I first had to tap out the back end of the intake because my original combination of ported Merlin heads and crossover would take out cylinder #6 #8 valves. With a infrared pyrometer the back of the heads was getting up to I believe 300°F during idle and would take a valve out within a minute once on plane. I replaced 3 or 4 valves during that experiment. (3 different failures) I then switched to Dart Pro 1 heads and ran the same setup. I always some restriction (5/16" hole) in the bypass hose. When I put my power in my Active Thunder from my Panther I then switched to E-tops and plumbed the intakes with -10AN (that's what the exhaust bung is) and had to put restrictors in to keep some heat in the rear of the engines and build a little engine temp. I have always plumed them into my exhaust. It is a fine line when you add the restrictors. It's a juggle between where your water is going and water pressure. Currently I have 3/16" holes on the rear of the intake and 5/16" in the crossover bypass. I just put them in the straight ends so I can remove and drill larger holes as necessary. I run about 15-20 psi H2O pressure. I noticed if it ran over 20 psi my oil temp would rise. I assumed I was restricting too much water and not flowing enough through the the oil cooler. I guess I wasn't hitting the optimum reynolds number for dynamic cooling efficiency.
I tried to search for my thread on Boatfreaks about the valve incident, head cooling and cooling passages but I don't believe there is a technical section there anymore. But I did find this beauty! lol
https://forums.boatfreaks.org/showthread.php?t=25599
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I did have an IR gun to monitor and regulate temps and I also run the 2/3-4/7 swap for the even cooling benefits.

Does any of this really change with closed cooling? Or are the issues more prevalent when using a crossover?