Sorry for the super late reply! Still not driving it.
1. the aluminum heads, when fitting these were the head bolts new or the old ones, the new ones are torque to yeald and should be replaced if removed, they should also have special hardened washers under the head of the bolt.
No clue, previous owner built it. There are arp washers under the heads. I might find out if I have to change the headgaskets.2. i need to see the inlet manifold you are using and the water pump, does the water pump have a elbow shaped hose from the top to the front of the inlet manifold next to the thermostat housing?
It does have an elbow.https://photos.app.goo.gl/fArDWZ560JMDX4mB23. is the thermostat housing the highest point on the engine disregarding the carb and uncooled intake manifold?
Yes, I believe so.https://photos.app.goo.gl/hy67gW6yh4QOSxKp14. are there any cooling pipes on the water pump other than the large port to the bottom of the radiator?
are there any water outlets on the inlet manifold adjacent to the thermostat housing?
I have a outlet going to the header tank from the intake, and on the water pump I have the thermostat bypass, and the inlet from the header tank's output.5. does the engine sit in the car with a "nose up" attitude?
Yes, such that the carb sits at a level plane.
https://photos.app.goo.gl/Oc7b06IrV23VpoYF3-------------------------------------------------------------------------------------------
now for the header tank
1. is it the highest point in the cooling system?
Yes. Notice behind the carb in this pic.https://photos.app.goo.gl/1Y1Rf4ntJMlBm8fh22. does the pressure cap fit on the header tank or somewhere else in the system like the radiator?
It is on the header tank. The radiator "cap" is essentially sealed off.3. how many quarts does the header tank hold?
Not much, probably 1.5? I wonder if I simply don't have enough coolant volume for a hopped up V8.--------------------------------------------------------------------------------------------------------
radiator
1. core dimensions and thickness
https://smile.amazon.com/gp/product/B003OAWYWA/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
Overall Size: 18.5” x 14.6” x 2.5” / Core Size: 13.78” x 14.09” / Rows: 3
Inlet & Outlet: 1.26” / Core Thickness: 1.2” / Tank Wall Thickness: 0.08”2. what is it made of?
Aluminum3. where are the tanks on the radiator?
On the top and bottom?4. is the top hose spigot on the radiator above, level with or below the thermostat housing?
Below.https://photos.app.goo.gl/56RTkt7dEGipvXLd2------------------------------------------------------------------------------------------------------
other stuff to check
1. when you purchased the new water pump did you buy it for a fuel injected engine, was it the same as the one that came off the engine and how does it compare to say a 66 mustang with a 289?
The one I purchased was for the year of the car I believe, but was to rotate in the correct direction.2. does the water pump have a "v" belt pulley or a serpentine pulley or is it a shorty pump?
It just wraps around the alternator, pump, and crank pulley.https://photos.app.goo.gl/cSfSDqDQQG1zaGWV23. the block, is there any traces of water in the oil because the 302 blocks suffered from core shift worse than most other engines, is the block from Mexico or Dearbourn as the Mexican blocks are much better?
No traces of water, and i'm not sure where it was manufactured.4. when they rebuilt the engine was it re bored and to what size as more than .030 over may have weakened the cylinder walls, usually on the back cylinders so you could have a pin hole in the cylinder which is sometimes exposed to above the rings and sometimes below the rings?
It was bored .030 from my understanding.5. are you sure that the electric fan or fans are moving air in the right direction, if you have a pusher and a puller they must be wired oppositely.
I'm sure the puller is working, and I removed the additional puller. The radiator is sealed enough that paper will stick to the front grill.6. is there a crossover passage at the rear of the inlet manifold or is it blanking off the water passages in the back of the heads?
I don't believe so, and the heads appear blanked off.Any idea if maybe I simply don't have enough coolant volume? How much coolant does it take to cool a hopped up v8? I have more pics if any more might help.