[cobraman428]

You need to experiment. It is time consuming but you need to determine if it is a coolant restriction issue or not enough air across the radiator issue. Many thermostats I believe restrict the amount of coolant needed to properly cool these big FE's.. Temporarily take the thermostat out and drive it. If it stays cool, then your problem is water flow. You may need to knock out the center of the thermostat and enlarge the hole but you will want some restriction. Just create more of an opening than a normal thermostat or find a thermostat with a larger center opening but definetly use a 160 degree. In my experience, 2700 cfm is still not enough.