what piston to get for stock jug ???

Yeah Stephen's right, Needs to be honed even if you dont need it. the only stick in the grroves for better lubrication, also lower heat temperature, Wiseco makes a great product but is a little pricey, It's a 170 for the kit and i think vito's is 120, dont take my word for it but i think so.
 
Take your cylinder to a machine shop and have them put a dial bore gauge on it. It may just need a good hone. I was able to get away with a new Wiseco and about 40 strokes with a flex hone after a piston melt down. I would go with the Wiesco. You can't get a better piston. I use them in all my small and big block chevy projects. It's a forged piston where most others are cast. It will be much more forgiving if you find your piston to wall is a little on the loose side. .035"-.045"
 
wiseco makes a great product. vitos pistosn arent nearly as good. go wiseco. may cost more, but in most cases you get what you pay for. cant go wrong with wiseco pistons...