Got great response on another forum, lots to "chew" on. I'm using dart 220s and super victor with massive porting. They did jacket all the water ports in the heads before they decked it. Looks rather impressive.
Since I posted this, I went back to machine shop and wanted all the details. They assured me that steam holes are not needed and they have been blocking them off for 30 years (a little bragging there). One of the reasons sited is the operating rpm of the engine. They assured me, unless I'm spending alot of idleing time, no steam will be there at all. I'm using a restrictor instead of thermostat on a triple bypass radiator and my operating rpm is 4500-8000 rpm (probably 7K). 1 of the options they gave me was filling the block to the bottom of water pump jackets but told me to wait til I go .040 over would be fine. They say that 350s they do for oval, 1/8 or 1/4 miles, they usually use block filler but with my siamesed cyclinders, I can wait til 040.
So, guess I got what I was looking for that makes sense. Should have just asked the guys at machine shop when I picked it up ay?