xlr8or,
I'm not disputing Bob's recommendation. By all means check the thermostat first, it's certainly the most likely cause and the simplest thing to fix. My first impression when I read that you installed the new heads and intake on your motor is that you may have installed late model parts from an LT-1 with the reverse flow cooling design. They would require the special reverse flow pump and drive system to work properly. Just a guess in case the thermo is not the problem. Good luck.
Mike
