I have to wonder whether the 341 is taller than the former 10 hp engine. I don't know what sheet metal issues you have but you should know this. Reproduction hoods, grille side panels and dash side panels are available from Steve Guider. Steve is a member here and goes under Horton20. If you wish to have his phone number, send me a PM.
Other than that, congrats and rescuing a 130 from almost sure death. I trust that you realize that the parts manual for that model is sitting in our Tech Section.