What's the difference?

I was looking at a 347 stroker kit for my engine and they have a balanced stroker kit, and a unbalanced stroker kit. What's the difference besides the obvious thing of one being balanced and one not being balanced? Does one make more power than the other?    

when some people talk about parts being "balanced", they are referring to them being extremely precise. for example, a crankshaft may be brand new and still in the box, but if you measured and weighed it thoroughly you may find that it is heavier and thicker on one side than the other... it will still perform very well, but will not reach its full potential until it is honed to such a precision that it is literally the exact thickness and weight that is was originally designed to be... this is why some vehicles are faster for no reason at all... did you ever know that guy in high school who had the same four cylinder truck as everyone else, but his was noticeably faster? and everyone thought it was because of his driving... but really, it was because he had a "sweet" engine... some people refer to this precision as "plumb" or "true"... you may notice at the track that when a car shuts off the engine completely stops all at once, whereas at the grocery store you may hear a car shut off the engine and it slowly idles down, sputtering until it dies. this is due to the car's engine being way out of balance... if the crankshaft is off by a little and the pistons, rods, camshaft, pushrods, and lifters are all off by just a little... then when you add all these little imperfections together, it becomes a much bigger problem for the overall engine creating a noticeably different sound... when you hear an engine shut off and it stops all at once, you know two things - this is an engine someone took their time with building, and this is an engine that is much stronger and more efficient that other engines of the exact same model... just because of the balancing that has taken place...
Does this answer your question?  

Yes it does. Thanks!  

Well, I hate to disagree, but balancing and blueprinting do not always mean the same thing.  A blueprinted engine is one returned back to the original blueprint specs for the engine.  When anything is mass produced, there has to be a range of tolerances, otherwise you throw out a lot of parts for not being perfect.

Considering the amount of rotating parts in just one engine, enough parts that are within tolerance, but not at spec, could result in a "monday" or "friday" engine that wears out sooner, as the parts fight against each other. A blueprinted engine may seem to have more power, just b/c the parts aren't fighting against each other, while they heat up and expand to larger sizes.

Balancing refers to just the rotating parts. Its like spinning a plate on the tip of your finger.  If there's a quarter glued to one side of the plate...its out of balance.  Now, while an engine is spinning, lets say 4000 RPM, there's oil splashing around inside the crankcase, its cycling thru the oil journals inside the part, landing on the part, getting flung off...in other words, the weight and how its dispersed, changes if you don't control how oil runs thru the engine.

If you're going to drop $7000 on an engine, then having it last b/c the parts are a precision fit, and balanced, is a good investment.  If you plan to keep spinning it past 4000 RPM, then it'll help to have it balanced and blueprinted.  If you plan to push this engine up near 500hp--where the stock Windsor block likes to crack its main webs unless you have screw in freeze plugs and a main cap girdle--then having it not fight itself, is going to help it last longer.