I'm currently looking to lift the rear bench of my truck about 5". I have found a kit offered by LMI but I refuse to pay $145 for some brackets. I've read that it is possible to raise it using C Channel, but I do not know how to accomplish it, any help would be appreciated

 

Not a perfect job but this will give you some food for thought...

 

Not a perfect job but this will give you some food for thought… the commercial kits I installed years ago also raised the back seat cushion and repositioned the latch assembly… much better design.