Welcome to the club, Mr Happy!
If memory serves the blazer drums would fit if one drilled the holes to 9/16 inch from 1/2 inch. The Blazer springs were coil, the springs on yours would be leaves and irrelevant. You should be able to use the coil spring drum with the same modification without incident. The NAPA part number is ND 4401071.
You may verify you have the original rear end as well, as the entire assembly may have been swapped out by a well intentioned previous owner.
Looking forward to pictures,
-Jeannie