if you're doing an LS engine to a NV3500, all you had to do was look at my build thread. 4.8 flywheel & clutch kit bolted right on to my 5.3. been running 16,000mi with no problems whatsoever
00 FRC - just top end, exhaust, and a hot-air intake
99 Sierra - 5.3 / 5spd
↓ click the pic for the build ↓