You would be better off splitting the case out of the 87 to make the reduction box from. It will have the necked down input which is weaker. Use the tcase from your rig with the bigger input behind it. The rear case will receive more touque and needs all the strength it can get.
You will have to grind the input shaft on the t-case to make it clear (slide) into the reduction box.
Wasn't trying to bash ya. It just sounded like you refered to the tcase as an L43.
