Balancing a Scat cast crank

At this point, knowing whether or not the stock 360 damper weight at the front, and the stock type TC or flexplate weight imbalance at the rear, are going to have adequate external balance weight is unknowable. You have a 4" stroke, which will require more external weights than the stock rods and pistons. You have lighter rods; pistons are unknown; either being lighter is going to help lower the needed external weight.

So it depends on the exact rod and piston on whether the stock 360 external balance parts will be adequate.

Of course, you can take the stock 360 pats and modify them to have more external weight.