Griz:
First of all, welcome to the landracing.com Forum. It's a fine place, if I do say so myself, to learn all sorts of stuff about our passion -- and also to find a good bunch of folks with whom you can share ideas and help.
Okay -- to your tire question. I don't have the answer, not being intimately familiar with the Bub's rules. In SCTA/ECTA rules, for instance, you'd need to determine in which class your bike will race -- and then get tires that are rated for the record speed in that class (whether your bike will get there or not isn't the question). I wouldn't be surprised if the Bub's rules are similar. Also, though -- at Bub's you can run in the "Run What you Brung" field -- which allows you some passes down the course so you can not only say to everyine that you've really, actually, honestly made a pass on the Bonneville Salt Flats -- but also you can run your bike the way it is, with only minor safety and other requirements.
I expect that someone that's more familiar with the Bub's (AMA) rules will answer your question. So - on the topic of you being a new guy -- where are you? Tell us a bit more about yourself. Maybe there's someone right in your area that can help you, too.