piston clearance

i have a 295cc robin engine,27 years old so not sure the past repairs.
i found 2 different size pistons, it did run but 1 hole had 150 lbs compression and the other had 120 lbs and at times ran bad.
the 120 lb hole piston was pretty sloppy.
the tighter piston has .005 piston to wall clearance, is that good or bad? it reads like a .25 oversize piston    
 
thanks