Okay, as promised I measured the distance between the top of the water pump housing and the bottom of the thermostat housing and it was between 7/16” - 9/16”. Basically 1/2” gap between the two points. Pre ‘68 Dave’s comment is spot on…… the shaft of the water pump is exactly in line with the head gasket. Now I know all I have to do is look at the water pump shaft to tell if the pump is high or low.

Thanks

Chuck
1950 Chevy 1/2 ton (all original)
1951 Chevy 1/2 ton (future streetrod)
1941 Chevy coupe
1938 Chevy coupe streetrod