[davepl]

Don't remove the radiator cap when hot, there's no "safe" way to do it no matter how old you are. Let those that claim otherwise keep at it, but don't imitate. I know someone who tried and failed, and fortunately only has minimal facial scarring.

- Make sure timing is set correctly, at least 6-8 BTDC, ideally a little more these days
- Make sure your fan clutch is working correctly, dragging when hot
- Make sure your fan shroud is in place and sealed up

If you don't have a shroud or you have some bogus flex fan in there, all bets are off. You need at LEAST the factory parts in place for the engine to cool properly.