FYI, when I built my 360 I used KB107 pistons and Eagle SIR rods both are lighter than stock. When I had it balanced they removed 200 grams from one end of the crank and 240 from the other end, that is almost a pound of metal. Can't imagine how that sucker would have vibrated at even 2000 rpm.
Spend the $200 to have it balanced.
In hind site I could have easily had my engine internally balanced with that amount of weight being removed for the external balance.
