That's the beauty of flex in a way

That's the beauty of flex in a way, there's no set gear level or ilvl you need to achieve. It's like a normal mode raid, if you can find a group for it, you can give it a try.
wow po
Now, I don't say that to be misleading, because the reality of course is people are not going to take you in 463 heroic blues, but my point is that it's a moving target. For Flex Wing 1, I typically see around 505-510 as the lowest required ilvl being asked for. Flex 2, usually 520+. Flex 3 is harder to say, anywhere from 520+ to 535+ is pretty common. Flex 4, usually 540+ minimum.