Outer Limits 4x4 Board

i have a 1993 modle gq tray with a tough dog 4 inch lift in it.
i am gettin little flex outta it in the rear.

it keeps cocking wheels up in the bush and the shits not very hard.
how and i fix this and get huge or better flex in the ass end.

cheers

sway bar's ????? disconects , or remove them
shocks to small ????? maybe longer shocks

mayb you have heavy duty springs in it ??

put some weight in the tray , tools ,fire wood, mother in law .... etc....