For an awesome, stunningly luxurious classic Cadillac, only the 'regular' things on this car have gone wrong.
I've never seen a 1968 Cadillac in person with the factory air conditioning functional. The A/C compressors are chronic trouble makers, and mine too was seized upon purchase (I've seen over 30 in person).
Small pits of front fender/rocker panel rust.
Valve guides worn from unleaded gas use (heads needed a rebuild and bronze guides).
Power trunk pulldown.
Vinyl top needed replacement due to average weathering (even though the vehicle was garaged 25 years).
Power door lock vacuum solenoids.
The mileage is... well... measured in GALLONS per MILE.
The 472 cubic inch big-block V8 is astounding. In 1968 and 1969 it was a virgin in the emissions department with 10.5 compression and an 850 CFM Quadrajet four-barrel. The torque is amazing and my burnouts have amazed many.
The comfort is second to none and beach trips are fun in the huge cruiser.
I was lucky enough to find one with all but a few factory options (Cruise Control, Controlled Differential, Seat Warmers, Automatic Level Control) but has beautiful Silverpine Green exterior with White Vinyl Top, Black Leather split benches front and rear, Guide-Matic, Twilight Sentinel, Power Windows/Seats/Locks/Mirrors, Power Trunk Release, Tilt and Telescopic Wheel and other Cadillacky options.
The last year for stacked headlights, first year for fabulous 472 V8, last year for real Rosewood interior trim makes the 1968 an incredible driver and collector's car.
Take the barge to the dragstrip and you'll be surprised what she can do underneath those fender skirts!