No difference between the -1 and -2, it is just a later production run. Sometimes Holley will make some small running change in their carbs, like moving the vacuum ports, and will designate a different dash number, but in this case the kits and all the body parts are identical. You just have a newer version. That wasn't the case with the old 3310 series. When they changed from -1 to -2 and up it was a totally different carb.

Don