I'm surprised by the number of posts. Let me qualify some of what I'm dealing with. First of all this Virus thing has put me out of work for months. So I'm trying hard to control what I have to spend. Thus I've looked hard to discover the identity of this gear or to reach someone who recognizes it. The gear and chain are in very good shape. Once again the description of the gear: 3 slots. A dot appears over the Zero degree slot. A second dot appears counter clockwise from it a few degrees and higher up toward the teeth. I opened the engine up and found the gear on the Zero degree keyway and the alignment set up with the other dot. This puts the engine at exactly TDC. Which seems to me to be the proper alignment. BUT why 2 marks? Second problem. And this one could be expensive (at least from my perspective) Used calipers on cam. Its a 564 lift CC. Simply checking height on each lobe I found 14 thousandths variation. Comp Cams says they think the limit should be 2 or 3 thousandths. What do you think? Anybody? I've got more questions. Haven't had to rebuild engine in 15 years. Forgotten a lot of little details for building a stroker.