Hi Growlers
Yes the lever arm needs to be lenghtened when you fit longer springs
The issue I was refering to is when you fit air bags and raise the loaded height
If you raise the rear (back to unloaded height to remove the sag) when loaded with the air bags the proportioning valve then bleeds off brake pressure as the
Valve thinks the vehicle is unloaded.
Of course if you have ABS no problem as no load sensing valve, however one more thing to go wrong
Joe