How many CFM for my 340?

I'm running only 60 PSI right now (25 PSI is minimum) and most of the lift you see is from the 6 leaf springs and slightly bigger rear shakels. Although, when I removed the old shocks, I noticed the right side upper shock bolt was loose to the body. After assembly it was still loose. Later I ended up putting a thick washer (spacer) in the trunk side to tighten it up. Back in the day - I had a 66 Dodge Coronet 500 (440, auto, 4:10.1 Dana), I put too much air (over 150 PSI) in the air shocks and hit a bump and boom, down it went. Tire clearance was a problem then and air shocks were cheaper than new springs at 21.