The very minimum needed to bolt in a V8 with stock parts:
K-member
Motor mount brackets off the engine.
Items that should be added:
V8 torsion bars
10" V8 drum brakes
Larger radiator
Larger rearend.
Things that are different between the /6 car and V8 car but the /6 stuff can be modified to work:
Engine wiring harness
Radiator
Chuck