PNJSNAK J im have a couple of things for you to check,
#1 what is the ratio of the pulleys on the front of the motor? Are you running a March setup? If so the water pumpcould be turning too slow and causing your hot problem. Ratio for crank to water should be a min of 1-1. Measure the diameter of both pulleys and get back to us.
#1A thermostats, They are not all the same. I have been through the overheating problem with my car. Everything helped a little but still got running in the 205-210F on the track and the motor was slow to cool off. When got back to the pits, put a box fan in front of the opening and ran it for 10-15 minutes with the motor off to cool the car down. I even tryed an $800.00 Griffin radiator. Agained helped a little but not the cure. The list I have givin you. Is all the things I tryed. IMO here's the winner that did the most,
Thermo stat housing is too small on the small flow side. This is for an FE motor but sure that same problem happens on all motors. I did the same repair for a Pont 400 motor and got great change in temp. High flow thermostats are just a sales pitch. Maybe they do and maybe they don't. I tryed them all. from Summit and jegs. I went back to the beginning. I got the correct diameter thermostat for the motor and started to look at all the other thermostats with 53-55MM size. I then looked at each one for the opening. I found that they are not all the same size. The FE thermostat is about 7/8". I then started measuring everything else on the rack and found that Dodge 383-440 motor have a thermostat that is 2MM larger and the opening is 1 1/4" That's alot of added flow. I got the thermo stat and trimmed 2MM to get it to fit in the manifold opening and cleared the housing. My motor at this time was a 452 FE with 9.2-1 compression small hydro flat tappet motor. All Torque. This motor is up to operating temps in about 2-3 minutes at idle depending on outside temps. The hotter the faster up the guage climbs. Here's the thing, once it hits about 190F on the gauge it drops back in to the 150's and goes back and forth until is levels out in the 180's which is what I am running. After 20 minutes on the track, I see about 205-208 temps. I do run an
oil cooler which also helps control the temp of the motor. I have gone to a 484 motor and still running the same numbers with about 150 more HP. I have finally solved my problems with the car.
Side note ERA has an air deflector for their cars, it works. You have to remove the dual small fans to get better air flow and this helps bend the air to the bottom of the radiator for more cooling. ERA has their radiators layed back at a 20+ degree angle and air doesn't like to bend. Another reason for a fan shroud and sealing around the opening inside the car with high temp foam strips or some kind of high temp tape.
#2 Some one all ready said up side down head gasket on the one side. They will go on either way but the steam holes are blocked . It's an easy mistake.
#3 Do you have the AUX dual cooling fans in the opening of the raditor. They look cool but block alot of air. Try removing them and retest the car.
#4 radiator shroud for the fan to pull 100% of the air through the fan.
#5 Fan CFMs, some of the guys Have gone to Tauras fans on there car These fans pull alot of air through the radiator. Not sure on hook up or how many amps this pulls. Need a good relay and recommend 10 gaue wire for hooking this and running it.
#6 if these ideas are not working from above and you pull the intake manifold to get to the head gaskets, check both the coolant passages on the head and intake manifold to match the gaskets in size. May need to get a dremmel tool and clean out the casting from when it was made.
I am going with the fact that you have gotten all the air out of the motor and this problem is still happening. YOu may want to goto a garage and have the coolant system vacuumed down to start and see if all the air is gone.
Good luck jim with the problem. I am going with my first couple of ideas here and you will be fixed. I hope it's not the head gasketed up side down. Think it's the arrow must be pointed to the front of the motor. Doesn't matter if you see it or not. Check with Fel-Pro site for side bars on installation. Rick L Ps I left off radiator caps, I like running a low pressure ones with 13 psi or 15psi. Anything more and I want to find a way to drop the pressures. This is not to say there is anything wrong with running a high pressure cap of 17 or higher. A couple of the guys run pressure gauges for the cooling system. this gives you an early warning sign about overheating a motor of head gasket is starting to blow.