My buddies and I did a swap for my LS. We replaced the headgasket and thermostat, and waterpump. Unfortunately, after five minutes of driving the engine got extremely HOT and the coolant flowed back to the radiator, and the temp. in the cluster showed the needle up all the way to "HOT". One of my buddies said it might be the headgasket. We checked and the headgasket is jerked a little. Any opinions? Thanks....!!!!