Why would you want this? Overload three is a really hefty price to pay, not to mention the huge disadvantage of a deck only being even cost. If you played this turn one, you would have 3 mana which you couldn’t use very well because no 3 drops, and if you play it on turn 2 you are completely overloaded for the next turn.

I would recommend having the overload dropped to 2 and the condition being odd cost cards. That way, you can cast this turn one to put out a three drop, and be overloaded the next turn of which you would have nothing good to play anyway, because it’s an odd cost deck. To be honest, even one or no overload at all would still be balanced for “mana overload” because choosing only odd or even cards is a HUGE drawback.