Hello and welcome to MBc.
Hmmmm, '93 Proflex. What model is that? Dual suspension with the cross link front fork?
Curious because I've only seen two Proflexes here, mine a '98 Animal and one that AlaskaVan has.
You will have to fabricate a spring loaded chain tensioner to push against the lower chain run. This will take up the varying chain slack created as the rear suspension cycles up and down.