Click on any thumbnail picture to enlarge (640x480) OR click on the picture name for a full-size (1800x1200) image

Balance Sheet
      Pistons and Pin     544 g
      Ring pack                53 g
      locs/oil support       12 g
      small end of rod    186 g
      big end of rod        462 g
      bearing                     40 g
      oil                               3 g

Total bobweight =     1802 g

Callies SBC Dragonslayer Estimated Bobweight = 1650-1680 g

Internally Balanced V8 Bobweight calculation:
     (Piston + Pin + Locs + Ring Pack + Rod Small-End ) + 2x(Rod Big-End + Rod Bearing) + oil

This comes from the theory that you want 100% of the rotating weight (Rod Big-End, Rod Bearing) plus 50% of the reciprocating weight (Piston, Pin, Locs, Ring Pack, Rod Small-End). Then because there are 2 pistons hanging on each journal, you want twice this weight, giving the formula above. For hi-rpm motors, some shops will use 51% or 52% of the reciprocating weight to "over-balance" the motor. This will require a 1.02x or 1.04x multiplier on the rotating weight in the above formula.

Externally balanced SBC V8 motors (383cid, 400cid, etc.) sometimes add an additional one-half of the Rod Small-End weight to the rotating weight calculation to compensate for the balance weight being farther away (damper and flexplate/flywheel) from the journals.
     (Piston + Pin + Locs + Ring Pack + Rod Small-End ) + 2x(Rod Big-End + Rod Bearing) + oil + Rod Small-End       ( Example-406sbc )

So because my crank's bobweight (~1650grams) was less than my rotating assembly's bobweight (1802grams), heavy metal (Mallory) had to be added to the large crank throws to increase the crank's bobweight. Mallory is about 2.5 times the weight of steel it replaces, and I needed two slugs of Mallory and then the excess weight was drilled out of several of the crank throws to reach the final bobweight balance.