I have a 91 4x4 p/u. I am gonna put a 2" lift shackle on so it matches the front which has cranked up T-bars and was wondering if i would have to extend the load sensing proportioning valve.. And if so do i just buy an extension.. thanks..

 

You can just fab a simple strap style bracket to raise the PPV back to where it was stock. If the axle to frame dimension goes up by 1" for example... you would need to move the PPV up 1" for it to work as it did stock.

There are other options, but this is the simplest way I am aware of.