i) alignment witht the belt is important -- Parallel to the engine's axis and orthagnol with the belt acess; and
ii) Belt tension is needs to be just enough to drive the compressor (that's why you shouldn't put other things on it; and,
iii) You need a compressor that is designed for the long-haul.

Seafrost, Technautics, and others indicate that this can be done.

As Dave suggests -- if it's working, why change the set-up. If the SeaFrost compressor lasted a while, why not replace it with the same item? SeaFrost is a very reputable company -- which, has (in my experience) always stood behind its well built, solid products. If you have a question about it, call Cleave Horton. He owns Seafrost. he was in Annapolis yesterday, but he'll probably be back in New Hampshire tomorrow morning. http://www.seafrost.com/menu.htm The engine driven page is http://www.seafrost.com/ed.htm