Rob, so long as the Alt. housing are similar (nose/front bearing support) and the shaft diameters are the same you should be able to switch them out. You may need to space the pulley in or out a little to line it up.
For the most part high output Alt. are usually OEM housing with a modified stator. Running a larger diameter pulley will change the output/RPM curve slightly due to the change in pulley diameter. Nothing I would be concerned about unless there's a radical difference.
Last edited by Rev; 06-21-2005 at 11:15 PM.