John,
What's the approximate time for a present day car?
Around 18 hours per car is considered competitive, just for assembly. Enormous strides have been made since then in automation in the Body and Paint shops; where a 60's Body Shop had 500-700 people per shift (most on spotweld guns), all welding and material handling is now robotic, and a typical Body Shop only has about 140 people, and only about half of those are production folks - the rest are skilled tradesmen tending to the robots. Paint Shops are about the same manpower comparison and level of automation - about the only manual operations today are sealing, and all spraying is automated; basecoats are waterborne, and clearcoat is 2-component catalyzed (and contains carcinogens) - no people in spray booths any more.
After the Paint Shop, Trim, Chassis, and Final Assembly operations are still mostly manual; selected operations (like windshield and backlite setting) are robotic, and many components are now received as ready-to-install "modules", with labor-intensive subassembly done by outside suppliers (seats, wheels/tires, instrument panels, bumper fascias, consoles, front and rear suspension assemblies, etc.).
