I didn't add and length to the shocks, they said the 4 and the 6" kits would use the same shocks.
I didn't adjust the links the BDS ones aren't adjustable!
I think the linkages themselves you replace to have added length? I can measure mine if you want. The part number for the 4" link arms is #013013 and the 6" arms are #013014 while the brackets for the frame are the same it looks like.
The shocks are definitely different length. When I was on the fence between the 4" or 6" BDS 4-link kits I put each part number side by side and compared the differences, that was one of them for sure. That was for me to compare how much it would cost to switch to a 6" when I get unhappy with the 4" lol but I ended up just going right for the 6" because I know that would happen in like 3 days.
For example, the Fox shocks for the 4" are part #98224700 and 25.22" long
The same type shocks for the 6" are part #98224750 which are 28" long.
This is my complete 6" kit, compare your parts and see what is different. The pitman arm drop is different, the sway bar drop is different, the brake line drop (if you're using OEM brake lines) is different, the bump stop drop is different, and you've gotta flip the cam around on the track bar drop bracket.
This is roughly from center of axle bolt, on the lower (longer) link arm