Cylinder

[Yfsblasterman]

I saw a video on youtube on ken o connor cylinders with the stock cyclinder and the vito`s 240 cyclinder , Now my question is .... He said you know if the cylinder is stock if it says y-1 on the left but mine says y-2 ? Why is this ?

 

[OConnor Racing]

Not sure why the number is different. Could be a different mold????????????