Unfortunately mistaken. Lots of dealers on west coast adding the J51 option code to vdoc's on 907s which weren't built with J51, for vans getting a big fuel tank. See my post #25 above. 220817a has ghosted on further theories to his post #21.I have yet to officially hear a dealer add J51 on a 907, since it is not listed as a retrofit item on Xentry. And it is not the same as a 906 where it is just cluster coding. Let me know if I'm mistaken on this......