Car was over heating at Idol, so i replaced the water pump, thermostat, got the radiator cleaned out Buttoned her up and no over hearing issues, found a frew leaks, disassembled/resembled. No leaks or heating problem. A few weeks later radiator begins to leak again. I replace the radiator yesterday with a 3 row alum one, idol for 20 min and it boiled over, gauge cluster is not in the car so a don't know what if it read, but i assume that the boiling over is no doubt over heated. The heater core was replaced 3 years ago.

should i just pull the thermostat and forget about it?
also what is the best way to clean out the water jackets (flush the system) with the motor still in the car?
BTW Stock 289, no fan shroud. I don't drive the car, she is still under construction just fire her up once in a while to get the juices flowing

 

Have you had the heads off recently? I'm thinking head gasket(s) installed backwards. Also, could just be rust/debris clogging the radiator... you said you had it cleaned out but what about the rest of the cooling system? the block tends to accumulate a bunch of crap, especially when it is not run regularly. Have you checked to see if you have a properly diluted antifreeze mix? too much water will cause more rusting in the system.
I'd take it to a shop that can truly flush the whole cooling system, then replace the thermostat again for good measure (they always go bad).

 

Did you get the cap with the radiator or did use reuse your old one?
Be a little careful, I have had 3 aftermarket alluminum radiators and none had std rad caps. The only rad that worked was the one that came with it own cap.

 

Car was over heating at Idol
You watch too much TV.

, so i replaced the water pump, thermostat, got the radiator cleaned out Buttoned her up and no over hearing issues, found a few leaks, disassembled/resembled. No leaks or heating problem. A few weeks later radiator begins to leak again.
Old radiator? It was it's time.

I replace the radiator yesterday with a 3 row alum one, idol [there's that TV show again] for 20 min and it boiled over
The coolant level in the radiator should be filled to 1" below the ring under the cap. Any more full than that, and normal expansion will give you fluid all over the place.

, gauge cluster is not in the car so a don't know what if it read, but i assume that the boiling over is no doubt over heated. The heater core was replaced 3 years ago.

should i just pull the thermostat and forget about it?
Bad idea. Removing the thermostat just means it will never be at the right temperature.

also what is the best way to clean out the water jackets (flush the system) with the motor still in the car?
Use a reverse flush through the hose connection on the top of the intake manifold.

BTW Stock 289, no fan shroud.
If the engine has been bored oversize, you'll need a 3-row radiator, shroud, and 6-blade fan, preferably a thermal clutch fan, and certainly not a 'flex' fan.

 

If it only over heats at idle it's usually a fan/shroud issue.

 

If i would have reached around and pulled my head out of my duffel bag i would have realized i had the thermostat in backwards

 

lulz

It happens. At least it wasn't an actual problem that required money to fix.