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Kinda sounds like a Ford PowerStroke at idle? Like a Diesel? Yeah, piston slap. Piston slap occurs when the piston-to-bore (PtB)clearance is greater than "optimal" (optimal being dead quiet in some situations). It is aggravated by JE pistons, which have a short piston skirt. The main benefit is that forged aluminum pistons by nature expand greater per unit heat than a standard cast piston, meaning you can run hotter overall with less detrimental effect versus an identically built motor with less piston to bore clearance.
When the PtB clearance is too little, there is no noise at all at idle - the engine sounds and runs like it is completely stock. There are no issues with cold engine and cold start performance (which you'll see if your motor slaps a lot - it doesn't seal well cold, and thusly doesn't make as much compression) or cold idle. Most engines built like this will last forever and then some, because it shows that they are built and toleranced very well. However, if the PtB clearance is just a hair too little, or the engine runs just a little too hot, the increased expansion factor can cause some very ugly problems - binding and breaking of piston rings, exaggerated cylinder bore and ring wear, and even in extreme cases, comlete seizure of the engine due to a completely bound piston (which usually results in the wrist pin being ripped out, and the then free moving rod making unhappy friends with some portion of your block). Of course, those are extreme situations.
When the PtB clearance is too much, the initial result is of course the noise. Your motor will sound like a diesel at idle. This is due to the similarity in what your motor is doing due to the increased PtB clearance, and the way a diesel motor fires - a diesel motor intakes only air(not air/fuel), and injects fuel at the moment of highest calculated combustion chamber pressure(TDC, or slightly after, depending on RPM), which of course results in the injected fuel, under so much pressure, to spontainiously ignite and make a loud "CLACK!" or "KNOCK!" (yeah, basically, it knocks by design!) due to the sudden jump in pressure beating the piston. When a cold, increased PtB clearance motor fires, the effect is not QUITE the same, but the sound is, due to the fact that the combustion forces act on the piston, and the PtB clearance allows enough room for the piston to actually cock SIDEWAYS, causing the upper edge of one axis and the lower skirt of the same axis to contact the block. it's not pinging or knocking, but the same WHACK! effect is occuring.
From what i understand, it is primarly a low engine speed problem, as the rotational momentum isn't there at low speeds (nor the ignition advance) to help the piston stay straight as the forces of combustion try to rapidly move it downward in its power stroke. However, you'll notice cold start issues (rough idle, decreased power under load, oil consumption) with medium-to-high PtB clearance. Once the engine reaches steady operating temp, though, the pistons will have expanded enough to create a better seal and better fill the cylinder bore. At temperature, they will not slap noticably (you'll hear it because you're trying to, but if you didn't know, you'd never hear it). Larger PtB clearances can also create issues similar to inadequate PtB's - too much space to cock to one side on the wrist pin can cause rings to bind and break or fracture. Too much PtB can also cause excessive blowby and oil consumption, and power loss due to lesser compression.
A happy medium is best, naturally. You want enough PtB clearance that the engine is quiet, seals well, and doesn't consume oil when cold, but also enough PtBc to insure your investment in the event of a cooling system failure (headgasket, waterpump, coolant line, low coolant, thermostat, etc) that could result in operating temps high enough to create unplanned-for expansion of the piston and ring set which could cause ring bind or breakange, or if temperatures are sufficiently high, binding and destruction of a piston and possibly the block shortly thereafter.
Will a slapping motor die sooner than a non-slapping motor? Depends on the application. a drag car doesn't have to worry about it - they need to make the most power possible in a short amount of time, and have a quick engine turnover. All dreams aside, we have street cars, and in my opinion a slightly gracious PtB clearance with a short skirt forged piston is a good thing, becuase you never know what might happen down the road... Someday that extra PtB might save your ass when you blow a heater hose and overheat (did that) or kill a thermostat and overheat (yeah, that too) or blow a headgasket and overheat (It overheats.. might be the hg.  ).. Mine has to get me to work. Better safe than sorry.
Anyway.. ______________________________
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Plus the rings were worn out
)
I had some help from my uncle also the most time consuming thing was the port and polishing it takes forever but I got pretty good at it, I suggest getting an electrical die grinder the air compressor gets annoying after awhile. haha that and looking for stuff took the most time.
but then again I bought the pistons and stuff used so I can't complain if I had to overbore i couldn't use em then. 
so complicated wish I had more money...