What is the difference between internal and external balance for the crankshaft?

 

exactly what it sounds like.

external uses a balancer to compensate for the weight of the rods and bolts. thats where you get your 28oz/in and 50oz/in cranks from.

internal balance means that heavy metal is added to the crank to balance it in of itself. all modular V8's are internal (neutral) balance.

neutral balance cranks have lower operating loads than one that has an external weight (think about how much weight is added and then how fast its rotating...). the only downside is that its expensive, but if you want to turn high rpms (6500+) you have to do it.