Unlike on a bench plane, the block plane irons should be placed bevel up. Block planes have their irons bedded at a lower angle. The standard block plane bed angle is 20 degrees while the low angle block plane has a 12 degree angle. By placing the iron bevel up, the effective cutting angle is determined by adding the bed angle and the bevel angle. For a standard block plane that would be roughly 45 degrees with a 25 bevel angle and 37 for a low angle block plane.
The ease of changing cutting angles on a block plane make these planes very versatile. With a low angle end grain is much easier to cut than with a standard angle. The same plane could then be used after increasing the bevel angle to plane difficult figured grain.