Not sure how rare it is, but I hadn't seen one before. I'd love a 1500XS, but not sure if that's the right motor for my CV project. Since this foot will go on any inline, I'm still thinking a later 86-87 ADI 115, which was 140 (86) and 150 (87) crank hp. So a little less revving than the XS, but the same crank rated HP. The real question is if I stick with a late style mid and integral trim, or go with the late 70's style that I already have and that opens up the possibility of a frankenmotor with a 15" mid and LWP. It's going on a setback bracket anyway, so I can position the engine for optimum height. Basically I have no idea what I'm going to do, so any suggestions are welcome! I think in the spring time if anyone has a lead on a nice 87 115, I'll be in the market!