Overheating during cam break in - help

I always place a big fan in front of the radiator to aid the cooling system while I'm doing the first start up and cam break in. Another thing, the easiest way to prevent a air lock in the cooling system is to drill a 1/8" hole in the outer part of the thermostat. I was taught this trick by an old timer over 40 years ago. Finally, I keep a water hose with a spray nozzle on it to mist the radiator if need be to get the cam break in completed.

This is something i always do!! A big squirrel cage blower (set on high speed) up against the radiator even if you have a fan and a shroud. You want to keep the new motor as cool as possible since they usually run hot during "break in" because of the close tolerances. Spraying water (mist) on the radiator also helps as long as you can still tell if you have water leak. If you have a water leak it will allow pressure to drop in the cooling system and the water will boil easier.
I've broken an engine in 10/15 minutes at a time because of carb/water/timing issues. They all came out OK as long as you keep the RPM up!! Never start a new motor without an oil pressure gauge and a water temp gauge. Also, no open headers....you can't hear a bad rattle or knock with open exhaust.

treblig