Now I know more but I am undecided...I'm running cast iron Vortec heads with stainless valves. Cast iron is forgiving with regard to heat withstand ...to a point. Does the volume of the raw water pump have any measurable effect on this "hot spot" issue?

Not as much as volume as making sure you get a good fill, no air pockets, thus the reason many add rear dumps to the rear of the intake. I did the same to my blower intake, tied the rear to the front.

So what you did is drill/tap new outlets in the intake rear water port cross over and dump into the exhaust ? I am visualizing that you created a loop back to the front so as to create even distribution?

Sounds like a good idea.

I'm running a crossover and my head temps are 12 to 15 degrees different right to left. Front to rear are within 5 degrees on the same head. The design of the Stainless Marine crossover favors flow to the even bank making it run cooler. I'm actually thinking about putting a restrictor in that bank to even out the temps. My engine builder says I'm too anal, has anyone else seen the same thing?

No,
Drilled/tapped the rear intake ports, then ran a tube on each side to the front ports to tie into. Not into the exhaust. Have heard several go that route, or even directly overboard to dump excess water press.


Volume, pressure, and a full fill.