BRG Racing makes the kit. It's not cheap, and some owners have worked out their own solutions, as the mounts aren't really that far off.
BRG 7/9 Kit
As far as a P motor fitting earlier models, you have basically the same issue with the mounts (at least for the L/M models) that the BRG kit solves on the P models . Of course, that means a B model 9R motor will bolt right into an L/M frame!
