does someone know the difference between a externally balanced crank and one that is not besides the obvious, I have a Gen V big block one piece seal, internally balanced, what would i need to do to use this externally balanced crank?

I have a Gen V crank 10114188 and I would like to use a 3967416. What do I need to do to use this crank?

thanks all for your help in advance
-Jason

Why would you want to externally balance it? If it is internal now just get a neutral balance flywheel and Harmonic balancer and go with it. The block does not matter if internal or external, this only refers to the rotating assembly, you can toss it in whatever block you want.

After rereading you post I think you may be misinformed. The block is not balanced one way or the other. If you have a gen 5 block with a one piece seal, and a factory crank to go in it then you are set. A factory GM forged crank will internally balance, but it takes so much heavy metal that it is not worth doing in my experience. Just get it externally balanced with a good Harmonic balancer and flywheel and it will work fine.

I crank that is internally balanced has a bunch more material on the counterweights to offset the weight of the rods and pistons. An externally balanced crank does not have enough material in the counterweights and has to use weight in the balancer and flywheel to balance the engine. To take a crank that was originally externally balanced and make it internal takes quite a bit of Mallory(heavy metal). You will spend more money in Mallory than the crank is worth.(it is about $60-$70 a slug) In order to take an internally balanced crank and balance it externally would need to have quite a bit of material removed from the counterweights, which would be a tremendous waste. Is that what you are trying to do? I am a little confused. I'm not sure why anyone would want to take an internally balanced crank and balance it externally.
Eddie

I have a internally balanced cast crank that is bad, I put a bunch of mods on the engine and I was thinking of putting the forged crank in it to beef it up. all forged cranks i find say they are externally balanced. so I didnt know what was needed to put this forged crank in my block? basically converting to an externally balanced crank! Any other thoughts or suggestions..

Thank you

you would need a balancer and flywheel for a external bal gen V or VI

If you want to go to ext. balanced, then as ezstriper said, all you need is a balancer and flywheel. Of course, it will need to be balanced.
On the other hand, internally balanced cranks are not the hard to find. You need a one piece seal crank in what stroke? You could also use a seal adapter in that block and install a two piece seal crank. The adapters are just under $100. If you ever plan on really stepping up the power in the future and what to replace the block to make more cubic inches, then you may want to use the seal adapter and two piece crank, since all of the aftermarket blocks(Dart, Merlin, Bowtie) use a two piece seal. That way you can use your existing crank and not have to buy another one.
Let me know what stroke you need and I can find a crank for you.
Eddie

the stroke size I need is 4.000" one piece seal, I was just hoping to find a killer deal on a forged crank to build my engine. but if i end up with just a stock cast than so be it.
"two piece crank" I'm assuming you mean 2 piece seal crank?

If cost is an issue go with a new scat nodular steel crank and have the assembly properly balanced. Unless you plan to spin over 5500rpm you will be just fine. They are around $250 last I checked. Go forged above 5500.

Get the forged crank. If you are starting from scratch get a stroker 4.25" crank, stock length HBeam rods, ofset pistons. Make it a 489 (.030 over) or 496 (.060 over). Your machine shop should know how to do this. He should also be able to explain the difference between internal and external ballance. If he does not I would find a new shop. Good luck with your build!!