Originally posted by MotorMatrix.com
at 84mm the walls are not as thick as stock. the difference between GE sleeves and stock are not the thickness. they are ductile iron so they wont split. also, if you go 84mm and you happen scratch the sleeve you will have to resleeve is most cases. at 81mm you can bore it over 2-3 times and still run boost.
it IS possible to run 84.5... but i do see your point...
-Keith