piston stamped 1.00?

[2000yfm350x]

tore my warrior engine down today, expecting to find bent valves, jumped time awhile back. and not only were my valves okay but my piston has a arrow pointing forward and 1.00 stamped in it, nothing else, ive seen other 350s stamped 1uy, mine is not, but a bunch of parts in my engine are stamped 1uy, like my valve faces etc but not the piston. its a cast piston and looks just like the stocker. do I have a 1.00mm over bore?

 

[Nick]

I would assume so I tore mine down to build it and I order a wiseco 12:1 CR piston that was a standard 83mm size and didn’t realize my piston was stamped with 50 and then check measurements and I have a 83.5mm piston and bore

 

[2000yfm350x]

I did measure my bore and it came out to be a 1mm over piston. it was just over 84mm