If you are using a factory GM forged crank it is not worth internal balancing. There is nothing wrong with using the GM crank, especially on a 550hp build, but to internally balance it you will have more heavy metal in it then a moderate line aftermarket crank like a Callies Compstar will cost you.

Just my experience with GM cranks.

Agreed Im not doing an internal balance
I have a stock GM forged steel 502 with dimple rods arp 7/16 rod bolts and forged ls6 pistons,
Im not doing anything crazy with the motor,
early casting large oval ports with port work 2.19, 1.88 valves
air gap intake,
850 holley dp carb
custom hyd roller cam from Bob Madera
should make 550hp or even a little more
gonna be between 9.75-10.1 compression,
I just have to have some very light marking milled out of the heads around where the fire ring is,
so depending on how much we take off will determine the compression,

should run pretty good for I want it to do
again nothing crazy just a pretty basic 454 motor with mostly stock GM parts that work well together

thanks for the help