Maybe someone knows the answer to this. It seems like thermostat
is not opening up. I have a eldebrock air gap manifold on a 383 with
a 180 stat. I don't have heater hoses hooked up yet only main top and
bottom radiator hoses. Should I drill hole in thermostat, or run a hose
from water pump into manifold? Maybe thermostat does not have
enough hot water in manifold to open it. Just waiting to scratch up
a little more money for vintage air unit. Water sensor is in head. The
temp goes to 220 before I shut it down, not driving the car yet, just
trying to get things lined out. Thanks, Bill

I just had the same problem with my new 327, I took thermostat out drilled it and ran car without it for a while to get the air out . I also left cap off the radiator and let idle till it came up to temp. good luck !

Hook up a by-pass hose from your intake back to the water pump. The 1 piece main blocks don't have a by-pass behind the water pump. Half your block is not getting good circulation without looping back to the water pump.

This should help.