Hello there. I am a new member as of today. And also new to this sport since one month ago. I bought a 1994 sn 701 a few months ago for pretty cheap. Tried it out a few times and love it. After I noticed my ski getting heavier. Did some research, and gutted out all the old foam. Was going to refoam it, but I picked up another hull. I was told it was a bob. Not to sure on what that is. But it's a 1996? Top hull, and a older sj650 bottom hull. It is supposed to be a round nose conversion. Now the problem. I am taking out the 701 from my first ski and installing it in the newer hull. But I came across a problem. The bearing housing inside the hull does not match up to the wall. The bearing housing has a number plate. Jd-2-c 62n 500190. Do I need a sj650 housing? What should I do. Any help would be much appreciated. Thanks.