Your engine, specifically the block, from the 84 will work just as well as a block from an '86-7 turbo car as they can usually support 500-600 hp with good internal parts.
The issue with the 1984-5 configuration in the intake manifold and turbo placement which make it very difficult and very expensive to get it to theHP level of an intercooled 1986-7.
You have a bigger issue as you just "picked" a specific turbo to plan your build instead of defining your performance as usage goals.?
This is like taking a trip and start out, but not knowing where you want to go!
Unlike a SBC or any carbed build, a turbo combination must have a group of compatible parts that will work together to give you the performance you desire. With a turbo build it is also necessary to define how you plan to use the final produce, street, strip and some other venue.
So far, what you have presented and asked cannot be adequately answered until you have some sort of plan or blueprint of what you are trying to accomplish.
