First, the facts
1970 Nova
th350 w/shift kit
95 2 blot main short block
world s/r torker heads
isky 270 cam
edelbrock performer intake
pete jackson gear drive
holley 850
manley guides and valves
3 row aluminum radiator w/ 16" electric fan
8 qt moroso oil pan
moroso high volume/ high pressure oil pump
15" ralley wheels

After I put this motor together, i had an oil pan leak. I had used the one piece seal from felpro. I lifted the motor up enough to get the pan off (along with removing the steering linkage). I removed and replaced the seal with another one piece from felpro. I finished after dark so I couldn't read the temp guage. On the way home, there was a good sized BOOM along with a lot of smoke. The motor shut off. I finally got it restarted (in the dark) and got to the nearest gas station. I saw the distributor was not completely down. I assumed that was the problem, fixed it, and got home. I usually run around 190 degrees, but it started running hot. My aluminum fan had quite a few holes over the years, which I "fixed" with bars leak. I changed out the old two core for a new 3 core and larger fan. I also changed to a 165 thermostat.

Prior to the changing of the oil pan, I had no overheating problems. After I changed out the radiator, it was still overheating, only when picking up speed or under a load. I could stop and let it idle and it would cool right down. I susected a blown head gasket. I had it tested and they found C02 in the overflow tank and said it was a blown head gasket. I spent the last two days changing out the head gaskets. I filled up the fluids and went for a test drive. Nothing changed. I get up to 250 degrees rather quickly when I am going over 45 mph or when I climb a hill. As soon as the load is taken away, it cools back down.

Any Ideas?