It might have liked the choke if it was on when cold. When warmed up if it lost the choke it might have got too lean and/or had a vacuum leak.
Also (hard to do) but make sure it has plenty of timing, that will keep it cool, hook the vac advance up too.
I always fill the rad with the heater hoses OPEN so you don't get air bubbles in the system. Or, the water temp sender in the head would be good to leave out.
Make sure a cool 160F or so thermostat is in there and actually OPENS at 160-170F, hen shut the cap so the system pressures up to avoid air pockets.
My other trick is to run the garden hose as high as it will go without spraying all over the fan, to keep the rad cool, run it right over the top of the rad.
Now that the cam lube is wiped off, I would fire it up again and finish the cam breakin soon as you can so the lobes don't get dried out.
