Rear shock length

Another silly question sorry guys

What's the general verdict on rear shocks for optimum length

I run mopar b body on my dart, and I think they do the job, as the rear body lifts showing the tyre, but........big but

Would it work better with say a truck shock? Or a 21" plus shock

My 60 foots are good, hooks well, lifts the front :)

But I want more ( as we all do )

Jack the car up and measure from your shock mounts down to the axle shock mount with the axle hanging down, that will be the overall size you will need when the shocks extended.