freshing up my gen 6 502, what are the best rings to use on stock JE700 pistons, building motor to 575-600hp. do i run je ones or aftermarket??

I use Total Seal CR5750.

Total seal rings are probably the best, but they're also expensive as hell. Running your Hp at 600 or so I'd say JE rings are fine. They make a good ring from my experience with them, a LOT better than stock.

what are the stock rings? are they not je rings, does gm put there own rings on??

The stock rings are by JE and they are metric. If you are still at the stock 4.470 bore, then you really don't have a big choice. I think JE and only one other makes replacement metric rings. Now, if you are at a larger bore and have pistons with a standard 1/16, 1/16, 3/16 ring pack, then I also only use the Total Seals. Let me know if I can help.
Eddie

stock 4.47 bore, so are the ones from gm the same as if i called je up and ordered a set or are the je ones better than what gm specs our je to make for the oem setup?? whats the best place to get je ones online

I'm sure Eddie can hook you up with parts, but when I rebuilt mine last year the best price I found to order the JE pistons was from here http://www.cnc-motorsports.com. They seem to be better priced than most marine places online and Summit Racing. I was told last year that je discontinued that stock piston, but i'm sure you can still get the rings.