If it isn't a turbo, the stock Toyota frame and drivetrain could probably with stand the torque, I remember even the dodge frames were twisting from the turbo early on.

V8 and 4.3 Vortecs take a 3" body lift and a straight axle for the V* to fit. Height may not be the issue, it will likely be the length.

If you really want the cummins diesel in a Toyota, you are going to have to find a T100 or Tundra. Depending on how heavy the cummins is, you will likely need an SAS to support the weight, even if you don't need a body lift to clear the engine.

If this is a non turbo Cummins, it may not even be worth installing it. A buddy of mine had one back in the mid '90's and it wasn't all that impressive on the highway power/towing or mileage wise.