I got a call one time on a 216 in a 40 Chevy sedan that would run hot in just a few minutes of starting it. The timing had moved because the owner had loosened the bolt to try and time it himself.
I reset the timing and it ran fine after that.
You have mentioned two or three times that you reset the timing when you adjusted the valves. Check that timing again. Is it hard to start? Does it have any power when it's running? When warmed up does it get hard to start?
My money lies on the timing being off.
