Can somebody tell me the reasoning why the headgaskets have different size holes for over different water jackets.

I just received head gaskets from "Moose" it seems they have one of the jackets blocked off and then another of the jackets just has one oval hole.

They included no instructions as to how to place this head gasket on the cylinder.

 

They have different size holes to evenly distribute the coolent across the head, otherwise all the coolent would flow up the exhaust side of the cylinder and out the front of the head. There should be a dot or a star on the gasket that is the top front, in other words dot faces the exhaust port, dot side up. If there is no mark on the gasket the smaller holes in the gasket face the exhaust side, larger holes face the carb/intake.