OBD-I is not standardized, there is no way DashCommand will work for you. You would need a product designed around your exact make and model of vehicle with a hardware that is specific to your exact vehicle.
Cody, perhaps you could have worded this a bit differently. DashCommand works perfectly fine with OBD-I cars as long as you have third party hardware to retrieve the data, ie: Zietronix, PLX and others. We use DashCommand for our OBD-I track car via the Zietronix ZT-2. We are more than happy with the results and love DashCommand's abilities to use custom skins.
I did an entire write-up on our setup here: http://4amracing.com/?p=712http://www.youtube.com/watch?v=sHDIZ0qv3W0