Do you need to use the lift block's on a 4inch lift if you are going to install AIRLIFT rear Air Springs? Thanks

YES you still need to lift the rear on the suspension.

If you try and use air helper bags for lift you will de-load the spring pack and the truck will not ride right and the rear will be floaty because the weight on the spring and shackle give the rear stability.

Thanks for the info. Also if i would do a tuff country 4inch lift and went with airlift 5000 bags do i need to get there lock-n-lift blocks in 2inch? thanks

yeap... What ever the rear lift block size is that is what you match the bag spacer to.

thank you for your help