I cant rememeber if I revers fed oil though the center or the ring part. I just have a aftermarket oil cooler plate and a filter on mine so I unbolted the oil cooler plate and filter to get in there. I was pouring oil right into the block its self and it did not take much to over flow. I then checked it by turning over the engine by hand and just that pushed some oil out of the hole. I belive I put the oil in the outer hole (the non threaded one) but am not 100%.
Hope this helps,
Jeremy
Hope this helps,
Jeremy