No you'd need to fit a turbo to get more out of your Om 352, the turbo could take her upto 160/170 ! But only if she has piston cooling jets without you could go to 150/160 this doesn't sound a lot but this engine is asthmatic at higher rpm and really benefits from forced induction and this makes a massive difference up hills.
Owning a Unimog for fun is always a good excuse and if it can earn its keep even better !
Re veg oil talk to Alaexander Noack he's a great guy very knowlagable (noack@anc.me)
Moose