1/2 hour labor - Raise car - remove wheels- replace car- done. VOTE for Mickey!..............I don't agree with either of those other fellas. I think it should be 6&1/2 hours regardless of if all 4 wheels are on it, or just 2.
Is it a 2WD or 4WD? It could be six or seven hours labor depending on that...I would also recommend resurfacing the flywheel and replacing the rear main seal. If the CV axleshafts are questionable, now is the best time to replace them.