Oh boy... ok i need some quick advice....

I have my engine almost entirely assembled (2.4L twincam LD9) and was just going thru some boxes cleaning stuff up, and i found the oil passage check valve for the head in a box. When the machine shop did my block, they took out all the plugs and such and gave them all to me in a box. Well somehow this valve got overlooked. As the machine shop explained to me, this valve goes in the block somewhere... (i think they said up in the deck where the head meets the block.... and basically this valve just keeps the oil in the head from draining back into the pan when you shut the car off. I didnt even know there was such a thing... so anyway... my engine is still on the engine stand, but otherwise 100% assembled. And now i find this part i forgot to put in... (honestly, i dont even know where it goes.)

My question is what would happen if i didnt have this valve? i mean obviously the oil would drain out of the head when i turned the car off... but what would that do to the engine and its health? Is it worth tearing the whole thing back apart just to put this in? or can i live without it?

and if someone can maybe tell me where this should go... that would be nice too.

I am really stressing out here... i was SOOO close... and now this... GAH!!!!

I've never heard of or seen that in a 2.4 motor, but I guess its possible....???

Got any pictures of said valve?