dragon 462 First off you have a brand new motor that is tight. It's going to run hot. With the motor running ,do you see the temp gauge drop when the thermostat opens? It should drop 20-25 degrees? is this happening? If not, Like others have said, make sure both head gaskets are on right. Are you running undersize pulleys?? This may be part of the problem because the coolant is not moving fast enought to remove the heat in the motor. There could be air pockets in the heads,block, intake manifold, or radiator. Is the water pump a high flow one? I have an all Alum motor and it was running hot, I went to a BB dodge thermostat. You have to trim the other ring 2mm to make it fit in the housing recess. It flows 30% more than the correct FE one. I run 2 gallons of water(distilled) 1 gallon of green coolant and 1 bottle of water wetter. I use a 180 thermostat and the motor hangs about 185 after racing. Drill a 1/8" hole in the thermostat to help get the air bubbles out of the system. You may need to burp the system, 4-5 times before the air is gone. I run under drive pulleys on my car. Do you run dual fans in the inlet of the car? Some of the racers say to use the splitter for the air, and the orginial dual fans don't do that much to cool. The splitter gets more air spread to the rad. The other possiblity is that the intake gasket is partially covering the return ports in the manifold between the heads and the intake for coolant. The
oil returns also need to be checked. The seen this happen too. Rick Lake Ps if you go to a auto zone or pepboys, get the stant thermostat for an FE and a Dodge BB 383-440 and look at the outlet for where the coolant goes through the housing. One hole is about 3/4" the other is 1" for the same temp. That's a BIG DIFFERENTS. My motor was running in the 220f
until I reworked the gaskets and changed the thermostat.
Oil return where also partial closed off.