hmmm....well EVERY core i5 overclocks to the same level, So its obviously 3.65ghz (Sarcasm)
Noone can tell you exactly, because every chip is different, I dont know your ambient temps, I dont know what case you have, for all i know you could live in a giant freezer.
Just set the Vcore manually to its stock voltage and raise the blck 5-10mhz and then boot into windows run a stress test program like prime95 or OCCT for about 15mins if its ok and temps are under 70C then go back into the BIOS and raise the blck another 5-10mhz, Keep doing this until it crashes/blue screens.
Then go back into the BIOS and back down your blck by 10mhz and test for stability for 12hours.
I wouldn't up the voltage with a stock cooler, just see how far you can go with stock voltage.