The 3 speeds they used for the art decos are at least partially syncroed. You would not be able to downshift from 2 to 1.
Is your 3/4 ton an open drive train, or torque tube setup. If it is open you would have more choices like a t-5, without having to change your rear end too. Look up Steppinwood and cavebull's art deco transmission swap pictures. You will get a good idea for what is involved for a t-5 swap.
