Depending on which ECU you have your datatransfer rate may be faster. GM's ALDL runs at two speeds, 160 baud and 8192. I have a 87 camaro which has the 8192 baud ECU, however it can also run at 160 if I choose (which I have used before). It has a data sample rate of about once per second, which really isnt all that fast. 8192 gets you around 10 samples per second which I've used as a sort of digital dash and it is fast enough for regular driving.