Are you using a Aftermarket T56, LT1 or LS1 Configured T56 ? Aftermarket and LT1 T56 will be the easiest to install, as you can used normal bellhousing and clutch setup.
If using a LS1 T56, The Flywheel, Clutch, Throwout bearing, Input shaft are setup a bit different.
Suggest you reseach if your not sure a this time.
It is possible that your Trans Tunnel may need so adjustments...