The 1st and 2nd generation PRV-6 engines did have the problem that you mentioned (plugged oil passegeways to the camshaft and thus caused the engine to self-destruct). However, the 3rd generation of these engines solved this problem and are very well built. The only 780s that came with the bad engines were the first year only 1986, but none of these were sent to the USA (Europe only for first year).

B27 is the 1st generation
B28 is the 2nd generation (ended production in '86)
B280 is the 3rd generation (built from '87 to '90)

I have a pair of 780s, one with the B280F (PRV-6), and the other with the B230FT (turbo-4). The 4-cylinder engine is easier to work on and has a higher peak-horsepower, but the 6-cylinder engine has better low end torque.

The car itself rides smooth and level. When compared to the 760 GLE sedans, it sits a bit lower to the ground and the body is significantly stiffer (overall vehicle weight is heavier than both the 760 sedans and wagons). The 780 is designed as a Touring car and should not be confused with a race car or high-performance car. If you enjoy taking long relaxing drives, then this car is for you. Do not buy it if you prefer racing the High-Schoolers at the stop lights.

Air Dams are easily damaged or destroied due to their design and how close they sit to the ground (one parking lot barrier will kill it, but they clear speed bumps decently). I know someone who just recently had his Air Dam replaced on his '91 780 and had it painted to match for about $3,200. Sheet metal, lights, and some interior parts are custom to the 780, and are somewhat rare since only about 12,000 vehicles were built worldwide (about 6,000 were sent to the USA). If you consider owning one of these cars for awhile, consider also buying a wrecked one just to have parts on hand if you get in a fender-bender. I know of a Doctor in Florida who owns six 780s. Three of them are driveable, and the other three are parts vehicles.

The hand stitched Italian leather seats are the most comfortable I've ever sat in, but the leather is softer than typical Volvo leather and they are prone to splitting if not cared for (regular leather treatments). You can re-cover the front seats with donor upholstry from a 760, but you must reuse the original seats to retain the function of the folding seat to allow access to the rear seat (the 780 is a 2-door coupe for those not familiar with it).

If you haven't already read the following website, it gives a good overview of the history of the 780 and the changes from year to year:

http://www.geocities.com/MotorCity/Garage/6570/about.html

God bless,
Fitz Fitzgerald.
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'87 245 Blue Wagon, 227K
'88 780 Black, PRV-6, 144K
'89 780 Black, Turbo-4, 94K