The wrench used on the nuts holding the fan on to the bracket bearing is 1/2" or 13mm used with the tow package
the four studs are maybe 1.25 inch long. I dont think these are metric studs
There is no water pump pulley on an LT1, it is driven directly off an internal gearing under the front engine cover
I think you mean the main engine pulley attachment of 3 bolts to the engine adapter the slides onto the crankshaft, and dont know what size they are, but easy enough to figure it out.