I forgot to mention that if you're rad. has some miles on it and the coolant came out looking more like "swamp water" then coolant, I would have it boiled out at a local rad. shop. If you have a buddy that works at an auto shop then pull a favor and have him make the call to the rad. shop for you to drop it off, pay for the job and pick it up. This will get you a few bucks off the job because they will charge the shop rate..
BTW: I ran 8.9:1 compression ratio and turbo with my car. I had one cooling issue when I had the 76 hood in mid summer heat with a slight rise in temps, I went to the 78 hood with vents and with the other things I had done, the car was driven often in over 100' summer heat in southern Louisiana with no issues from that point on.
My cooling mods:
Local built 4 core rad. made from a stock rad.
Large Hayden electric fan infront of the rad. on a thermostat switch.
Nissan water pump
Pink coolant extra long life (borrowed from work, don't tell anyone)
New Nissan thermostat
Oil cooler (custom job made from a 83 Jaguar cooler)
Hood vents
Hope this helps.