Normally, about the time that the flywheel clears the Flywheel Cover (aka Bell Housing in the auto world)........, the Borg Warner splines at both the PDS (primary drive shaft), and the B/W Drive Coupler, have also cleared one another.
2" is close, but certainly worth trying!
I assume that this 2" is with the Crankshaft Pump removed????
Are you installing new PDS bearings/seals??????
Yes, I would definitely be removing the exhaust risers!
Also, as an FYI for you......, note the common issues with the OEM Riser-to-Y-pipe rubber couplers.
These should be replaced, and purchased by the foot, NOT by P/N!
The Sierra and OEMs are too short and cause issues.