The bottom mount you can get from a P39Plus or a Poulan Pro 405. It is the same mount and I assume it is the new 30% glass-filled nylon mount. The old style magnesium mount will also fit and you have much more selection. Any regular P39, P41,P42 or farmsaw mount will fit and work. For the side cover, do you need just the plastic housing that the starter is part of, or do you need the complete thing with all the starter parts included? It seems to be a unique unit for that model, but I would think that a P41,P42 model could be made to fit. Not sure if the P45 is a bigger frame model than the P41,42 series or not. I don't think a complete starter assembly is available any longer, but parts may be still.