I used the shorter bags to give me more suspension articulation when deflated (5psi) When aired up (15-20psi) the bags “stiffen” up the springs to prevent rear end sag when towing. I also added an adjustable blow off valve set to 30psi to prevent over inflation.
I’m running the 3” slinky HDs with the following airlift bags:
Air Lift 1000 Air Suspension Kit 60728
Working great so far. I did plumb the air lines from the top, opposite of the instructions. Both bags are on a separate regulator connected to an air lift controller:
AIR LIFT 26229...
Both front seats from a 1995 80 series. Recently reupholstered, powered mechanisms cleaned, lubed and rebuilt with gramiviti gears. Fixed sagging cargo nets with new shock cords. Also has unobtainable wits end seat risers on the driver’s side for added room and comfort. No seat belts, swap...
You can take the bumpstop apart and remove the lower metal cup that is rubbing the spring. You can also bend the stop on your bench or shim it when reinstalling. Easy to do but you need to remove the spring to get to it.
QPM circuit breaker is fed via fused (150A) power right at battery terminal. Breaker provides additional localized protection and ease of power disconnect.