I used to use a very conservative machine shop back in the 80s and 90s. The owner had a very good small shop. When I bought my first vortech supercharger back in 91, I was talking to him about boost. He said you can't run that much boost on your 9:1 pump gas engine. The compression will by to much for 93 octane. He took out a boost/compression chart. He said I could safely run 3lbs lol. I said thank you for your help and went home and put the 8lb pulley on!!!. I ran it that way for a few years till the updated blower came out and increased it to 12lbs. It lived a long time like that (conservative tune) . 😃