Alternator belt tension

[SBSerpent]

?? For a 392 with a V-belt. Should I be able to spin the alternator pulley with the proper tension? Or, should it not be moveable? Is it 1/2" slack on the belt at the longest stretch between pulleys? Inquiring minds would like to know.

[spdbrake]

The belt should be tight enough that when you push down on the belt with your thumb in the span between the Alt and water pump you can only deflect it about a 1/2 inch applying about 10lbs of pressure. And no, the alternator or any accessory should not be spin-able by hand with a belt installed.