There is also one in Iowa City - Dynomike Power Tuning, owner is in our car club. Mike is a good guy but you will need to talk to him about what you need to have done.
I won a free hour on the dyno at the local cruise-in so we put my '56 Pontiac wagon on the dyno. Restored car, we tried to tune out some carb issues (ended up replacing the carb the following year) as well as figure out how far off my speedometer was (about 15%).
Phone: 319-621-3441
Website needs updating:
http://www.dynomikepowertuning.com/