What kinda coils do you have? One big one (Magnavox D552)
or 3 seperate ones(AC Delco D555)
If you have the AC Delco ones the MSD will mount right up if not you will have to find the AC Delco on it should plug right in. I switch my friends out from the magnavox to the AC delco and he said he could tell a performance difference in the two.
Here are the AC Delco Part and GM part numbers.