What are your reasons for using corvette engine? Is it the power ?
Putting an sports car engine into Silverado will not make sense and here are my reasons. Sports car engines have a shorter connecting rod than those of a bigger vehicles with heavy body. Shorter connecting rod are design for gaining a shorter stroke, meaning trucks have a longer connecting rod for longer stroke which is necessary to maintain sustainable power throughout RPM.
I strongly suggests to just rebuild the original engine with crank kit. A well balance engine rebuild can give you more power than needed.
For 2wd to 4wd conversion, you wheel need all the drive train from a 4wd. You will need 4x4 transmission, front and rear axles.
The cost for the conversion will be between $8K to $10K dollars. Of course, you can cut this cost tremendously by finding a good donor that is already a 4x4 and spend your money on the engine build.