I measured out the engine mounting holes but a problem here is that the Roto engine mount system is very wide and not in an ideal place. I have put two pilot holes in place on the firewall so far, the third hole sits over the side wall so will require dremel work and the forth hole is out in open air. I also found that the Roto is setup for M5 mounting holes and I don't have any hardware on hand for that. I ordered some in and have also picked up some wood to make up the mount extension. So at the moment it's a waiting game, once I have the M5 hardware I can make a start on suring up the mount.