First off, wrong forumn, check out the 1st-gen/4G63 forumn off the top page. I would think that there shouldn't be any 'play' in the belt at all, as the tensioner should take up any slop. Do the cam gears move enough to suggest that the whole belt is pulling to give you 1/2in. play, or is there just that much between the gears? Does it run funny/ have a weird lope? Any CEL's? Either way doesn't sound to encouraging to me, just have the timing belt replaced and be done with it.