If I were to box the whole frame and run F1 springs in the rear with airbags to help increase the load when needed but give the truck a little movement in the rear suspension. The F3 rear suspension doesn't give at all unless it's really loaded down. The front springs are getting replaced since they are so worn out. I will have to do something with those for the added weight of the motor.

Any thought?

I know I keep jumping back and forth on what I want to do with the frame but I'm in the initial planning stages. I want to be ready as much as I can when it's time to get going.