its not the hose and clamp
those old j-bodies have shitty plastic heater cores,.. it's probaly broken - we have 2 of them (boosted 92 and 93 vert).
this is what you need to do:
buy a new 'metal' heater core from CT,.. probably cost you a little over $40 (i think)
and 2 new heater core hoses and clamps
cut off the old hoses
to access the heater core you need to go underneath the dash and undo the bottom of the heater box,.. tight fit
before you pry the heater core, it's bolted on the enginebay side by 1 or 2 10mm bolts.(near the hoses)
there are a couple guys on this site that can probably help
www.hotwheelz.ca99% of them have had gm j-bodies