If it was me, I would not buy a righty ball and then plug it all up and drill it up lefty. Thats alot of plugwork especially if it has a weighthole to be plugged as well. If the plugwork is done well, it probably will not affect the roll of the ball, but if its shoddy plugwork, you will have problems. I know alot of people say if you do that your track area with be just fine, but I would wait until you find a lefty drilled one. They are around, trust me. Just have to look and be patient..
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One day when I grow up I hope to be able to throw the ball AND carry as good as g_thing!!