Coolant in the oil. Need some help.

So I have done the mini me swap on my 95 civic ex and I have the d15b7 block, with a d16z6 vtec head. Got everything together and bolted up no problem, and it started and ran like a champ. Where I run into my problem is when I went to top off the coolant, it just kept on an kept on taking it, but not losing it anywhere. The car wasn't smoking or leaking that I could see. Turn off the car and the oil is slap ass full of coolant. I know typically some coolant in the oil is a head gasket problem, but it was not smoking, and it was taking the coolant into the oil as fast as I could pour it in. Took is back apart and everything looks fine. So now I'm lost. What in the world could it be?