84 Big Red 200 piston size

[hfd410]

I need to get a new piston for my 84 big red 200es. The rings grooves are trashed. The bore is nice and smooth with no damage. Can anyone tell me about the numbers on top of the piston? In the center it has 5949E. On outer edge it has 4289M06600. I just need to know what size to order, not sure if cylinder has ever been bored and do not have way to measure bore. Thanks

[atc500x]

you have a wiseco piston
4289m06600 = 66 mm bore (4th oversize)
stock is 65mm

[hfd410]

Thanks alot, have one coming....