We're building a GTV6 for the next race and I would like to know what I should do to the motor to make sure it'll run for the entire race. I'm already planning on a new timing belt and to check on the water pump. We're also going to make sure the radiator is in good shape and that the coolant hoses are new. Since this is the first v6 I've ever worked on I'm in new territory here. What else do I need to know about these motors?
We run ours pretty much stock.
I'd strongly suggest replacing the water pump, not just inspecting it. Also, take a good look at the tensioner while you're in there. Replace the water pump and timing belt, set the belt a little on the loose side, and you should have no worries - the motor is pretty much bullet proof.
Other than that, make sure all the electronics and connections are in good condition. In my experience, most V6 problems are the result of bad sensors, bad connections to the sensors, or timing belt/water pump problems.