Need help to fix my overheating on my 216. Bought and Install 1938 truck 216 that was rebuilt, and I rebuilt the water pump installed engine and overheated, coolant out tailpipe. Pulled head, had welded and reinstalled. Overheated again at same driving distance 3 miles, pushes coolant out over flow. Brought high efficiency radiator and the 5th thermostat 160/180 degree and bought a rebuilt water pump. Overheated again, not as bad, just over 220 degree. installed 180 degree thermostat and overheated 200 degree. Check OEM temp gauge with temp gun, both read the same. Installed 14 inch electric fan to lower part of radiator as a pusher (run fan with key on) run OEM cooling fan and 180 stat, drove and runs at 200 and 220 at idle. The rebuilt water pump impeller fins that run next to engine block are 1/8 shorter than OEM fin, but the rebuilt impeller I used is the same as the rebuilt I bought. Is this the problem that the pump doesn't pulling enough water OUT of the block? HELP