Even though the name is really ironic, /u/ShutupPussy gave the best tip. If you really know your part inside out you can pretty much nail this. I'm a first year student at University and have to present like every other week. Usually I practice 2/3 days in advance by using a timer (for my time limit) and reading my part, that I have writte out, out loud. For me, this trick helped me a lot, it identified where my stutter was in the presentation, and then I kept practicing and practicing. Sometimes I even changed the sentence to 'fit' my speech. However, I have a light to moderate stutter so your case seems more severe than mine, but I think this should help at least a bit.