Water pump pulley

[1] Yes, the article in post #15 is wrong. It ignores a fundamental point: if the coolant stays in the rad longer [ to supposedly get rid of the heat ], then the coolant in the engine will gets hotter because it is a closed circuit. Now, hotter coolant enters the rad for cooling than would otherwise be the case.
[2] Many people who hardblock their blocks report cooler running. Since most of the coolant volume is in the block, a large proportion of coolant [ for cooling ] has been removed from circulation [ pardon the pun ]. So how can that be, less coolant, runs cooler? The remaining coolant circulates more quickly because there is less of it & cooling is improved.
[3] Using a 1" spacer & it runs cooler. The 1" is about the open area of an open thermostat. If you add up the area of the coolant holes in the head gasket, that area is greater than the stat area. So the stat regulates flow, not the gasket holes, but more importantly the restriction of the hole/stat creates a pressure build up in the coolant. Hot spots can form in the heads, & cause localised boiling [ nucleate boiling ]. Boiling water contains air bubbles, a poor conductor of heat. By building pressure in the system, the bubbles are suppressed & cooling is improved. They were pretty smart those factory engineers!
[4] Go to tech tips on this website. Started by Howard Stewart, who made the Stewart racing water pumps & built his own WP dyno.
www.stewartcomponents.com