Drive shafts should not be a problem there is a great number of OEM components to built just about any shaft. I would most likely go with custom manufactured aluminum or composite shafts and make old shafts garage sale item.
Precise shaft balancing is mandatory becose 4.3 axles ratio.
TOD might be a week point of this setup, I can see burned clutches already! I think that complete manual xmission out of a GMC 4x4 together with manual hub locks might be a better choice.
In this conversion the overall gear rations need to be examined against torque curves of the LT1.

DANA