Why are there so few blown small blocks?

What did this car run with the blower on it?
Unfortunately I only got 2 passes and neither were very good. I didn't even keep the time slips. I ran up against a family imposed age limit and didn't see any sense in working on it further. I'm going to go back to NA with carb and probably put the race car up for sale. It should run hi 9's with the single carb configuration.