[uttergto]

I wish someone could offer some suggestions that I haven't tried yet. The heating problem occurs when driving on the freeway at a cruising RPM of about 3,000 at 75 deg air temp for about 20 miles or greater. I have done the following:

1. Installed SS spacer plates in the front cover.
2. Changed three different water pumps with different impeller configurations.
3. Re-gapped the spacer plate to the water pump impeller from .187 to .080-in.
4. Purchased a new fan clutch.
5. Installed a temperature gauge in the radiator outlet hose to monitor cooling across the radiator.
6. Added a fan shroud.
7. Flushed the cooling system with muriatic acid.
8. Flushed the cooling system with plain water and bursts of compressed air.
9. Changed from an anti-freeze to a water-wetter solution.
10. Made an adapter to solid mount the original aluminum 7-blade fan.
11. Checked the thermostat in hot water for proper opening temperature.
12. Tried putting two different size orifices at the radiator inlet, 3/8 and 1/2-in.
13. Checked the intake manifold temperature sending unit for proper output.