On my new motor I went back to iron heads. I was using ported AFR 190cc heads be was not satisfied with the results. I cam across a set of ported iron heads with 2.05/1.60 valves CNC ported and flowing 267cfms intake/206cfms exhaust @.550 lift. They were giving to me because the person who had them before me ran them lean and they cracked between the valves on #1 and #2 cylinders. My machinist said it was no problem to correct. So I had them repaired with new seats, valves, guides and springs good to a .620 lift three angle valve job and trued. I had a .40 overbore LT1 forged and installed the refurbished heads.
The car runs great and ran a 12.94@105 last week at the strip. The two things that bother me are one the car runs warm. With a 160 degree t'stat in traffic it will run at 195-200 degrees with the fams on and set to come on at 180 degrees. Two it seems like about every two weeks or so I am adding coolant/water because the resivoir is low. I never smell coolant or see any white smote ot of the exhaust. I know the heads were cut to death. My compresson is 11.5 to 1. And I am still running the stock radiator. I even went as far as to drain the radiator and put in two bottles of WATER WETTER and top off with distilled water. the temp has come down maybe 5 degrees. On the road running at 70-75 mph it will run at about 170 degrees. In traffic 200 easy. Any ideas on what to look for. Or has anyone else had this problem. Help please. Thanks and sorry for being so long winded.
HVY SS

 

check your freeze plugs

 

if your having to add coolant it is either leaking internal or external I'm sure you will agree.

Pressure test your cooling system to see what leakage you have.

 

You should be able to see some whitish buildup on one of the plugs if it's burning it. Just want you wanted to hear, huh.

Might be worth looking into a new delco waterpump. Failing waterpumps can leak onto the road and give poor idle output right before total failure. And it's almost easier than checking the plugs.

Are you sure both fans are working? One bad fan would do the temperature symptom you describe, but doesn't explain the antifreeze loss. But it's an easy check.
Good Luck!