I have BILSTEIN on my truck at present, but the new KONI FSD
would be an upgrade. Available for GM and DODGE trucks in 3/4 & 1T.
The "lever arm" of the trailer ball-coupler-to-axle-center distance
has a good bit to do with this. A non-compliant suspension makes it worse (so get the WDH dialled in correctly), and, put some
TT's together with some
TV's and the problem is magnified.
Moho's are affected by porpoising as are tractor trailers (try mis-gauging the axle load on one of those and it'll pound you to beans). Better shock absorbers (past loading/rigging details) are the next best step.
I hate it as much as anyone. Oklahoma turnpikes can be bad on this.