As an owner of a pair of 780 Bertones, I'll do my best to answer your questions and the ones asked or implied by other posters.

1. What engine is in the '87 780 and what kind of integrity does it have?
This is the B280, the 3rd and final generation of the PRV-6 series. As mentioned before in the prior posts, stay away from the B27, and B28 due to poor oiling to the camshafts and a non-even-firing system that can lead to snapped timing chains. The B280 was built from 1987 through 1990 and has no mentionable issues. It's a reliable engine as long as you don't neglect it and miss oil changes. However, replacing a head gasket requires special tools and time that most mechanics don't have. The water jacketed cylinders are shimmed and sealed at the bottom and use a head gasket at the top. There are many B280s out there with over 300,000 miles, and they are one of the smoothest running engines you'll ever drive.

2. Is the engine wiring harness an issue? (on this particular '87 vehicle?)
Yes, any Volvo built from 1980 through 1987 probably has a biodegradable wiring harness installed (unless its already been replaced/upgraded). Volvo has an unusually good commitment to the environment, but this was one program that backfired on them and the harnesses start to loose insulation as they get old (accelerated by heat). However, swapping in a harness from an '88 or later B280 should solve the problem, and it should be the same as a 760 GLE harness.

3. How much time and money would this car require to own/maintain?
If you buy a 780, it's going to be your new hobby. -whether you want it or not. Less than 10,000 vehicles were built, and only half of those were imported to the USA. Used parts are VERY VERY rare for this car when dealing with sheet metal, glass, head/tail lights, interior parts, and trim. You will spend your spare time on your vacations visiting salvage yards to hunt and peck out the misc pieces and parts that you're looking for. If your car doesn't come with an intact Air Dam, you're probably going to spend a lot of time without one or be willing to spend a lot of money (between $1k and $3k depending on your parts source and labor to paint/install it). It sits low to the ground and is easily damaged by parking lot barriers and curbs. Unless the car is in immaculate condition, you're going to spend a lot of time surfing the web, checking ebay, and hoping to pick up parts cheaper than what the dealership charges.

4. "If the engine is questionable... would this car not be an excellent candidate for a V8 swap? Talk about the ultimate project -- with very little investment."
This has been done, and the head mechanic at my local Volvo dealer owns such a vehicle. Finding a replacement used B280 engine isn't that difficult since they find their way into scrap yards and nobody is looking for them. Other options abound, and converting it to a B230FT shouldn't be too difficult either (also done before). Endless possibilities abound, but if you do put another engine into the vehicle aside from the B280, make sure you have the donor vehicle sitting side by side with the 780 for wiring harness comparisons, cable routing, and all the other little odds and ends that turn up in such a project.

Finally, with all that said, a 780 is a wonderful vehicle to own and drive. I enjoy mine, but it isn't my daily driver. It's not typical, it's not flashy and thus doesn't overtly stand out in a crowd, and it's a lot of fun to go driving in with the windows down and the moonroof open. It was designed to be a true "Touring" car, and is not something that you would find in "The Fast and the Furious." The seats are 2nd to none, but the leather tears easily if it doesn't get regular leather treatments. The Birch Burl wood on the dash is real, and the sound system rivals a lot of newer vehicles (but it merits changing out the speakers if they're getting old and tired). If you haven't already read the "Unofficial 780 Website," it's worth your time to take a read through.

God bless,
Fitz Fitzgerald.
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'87 Blue 240 Wagon, 252k miles.
'88 Black 780, PRV-6, 146k miles.
'89 Black 780, Turbo4, 94k miles (accident vehicle that I'm restoring).

having been a volvo mechanic for more years than i can remember,the b-280 is a fine engine however parts are high and it is a very labor intensive eng.like the others said finding parts for body and so on is an experience.the 240 probably is not as fun,but alot more practical.then on the other hand 600? well that might be a good deal.of course there is always the couch!

If the engine is questionable... would this car not be an excellent candidate for a V8 swap? Talk about the ultimate project -- with very little investment.

Just a thought.

Jeff Pierce
--
'93 945 Turbo ( one kickass family car ! ), '92 Mercedes 190E (my daily driver), '53 Willys-Overland Pickup (my snow-plow truck/conversation piece -- sold to a loving home), '85 Jeep CJ-7 w/ Fisher plow

Some things to consider; the Bertone is a rare body style. Parts & trim will be hard to find.
Mechanical parts are shared with 700 series.
The V6 engine uses cylinder liners which must be sealed at the base and the head. If the head is removed, extra care must be taken not to disturb the liners.(slide the head sideways when removing-dont pull up).Otherwise the engine must be completely removed to reseat and reseal the liners.
The early versions of this engine -B28- had oil passages that were too small in the cylinder head, and this lead to premature cam wear.The heads must be removed to replace the cams, because they slide out of a hole in the head, and would hit the firewall. ( my brother told me you can cut holes in the firewall- WTF?)
Since I own one these dreaded PRV V6's, I recently decided to remove a valve cover and check the cams. Guess what? After 130,000 miles, I see hardly any wear. Wish I could say that about my goodwrench engine! I suppose the problem was fixed by the time my engine was made. '86
I think you can see why so much hysteria surrounds this engine, it could be very labor intensive to repair, and requires much more mechanical ability than the inline 4, turbo or not.
After '87 the engine was changed to electronic fuel injection (pre '87 was mechanical CIS-still very dependable). The cams and firing order were changed to create a smoother running engine. The distributor was moved to the front of the engine.
If this car has "a hole in the engine" I would think the block may be cracked, maybe from lack of antifreeze. If it runs it can't be a thrown rod.
The Bertones are beautiful cars, but this one could be a money pit.Be carefull!

Greg,
I just gave my 88 780 to a charity. Poor thing. The interior things are unique to this model. The electrical and engine are the same as the 760 of the same year. Body parts are hard to come by. They have all of the mechanical problems of a 760 rear drive auto, plus electrical seat problems which are unique. It has a power glide seat switch which moves the seat forward when tilted forward, and back to original position. The rear seat only holds two small people comfortably.
The V6 engine has a lot of torque and is pretty good. It only gets about 20mpg on the highway. The turbo-4 is a little bit faster. The real problem? A 1987-88 V6 is worth less than $2000 if it is in very good condition. You will never get your monies worth out of it. Keep your 240 and be blessed you didn't make a mistake.

Klaus
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98 V70Rawd(101Kmi), 95 854T(85K mi), 75 164E(173K mi)

I'd buy it in a minute at that price if it were structurally sound but needed an engine, but I have no more kids at home, and it would not have to be a daily driver. I would be really careful, though, if it meant either using grocery money to get it running or swapping out a known good daily ride. The kids gotta come first (hmmm, are any of them old enough to hold a wrench so you can make this into "quality time"?)
--
We have met the enemy and they is us. [Pogo] S70 T5 cop car : Rough Rider suspension, Walmart fog lights, eBay speakers, ambiance by Pall Mall, trim by Le Duc d'Tape, 8-channel THD by OEM amps

hey check it out... Ive seen these with the 4 cylinder motors, and I'd my self would run as fast as you can away from those 6 cylinder ones

It is the undesirable 6 cylinder version ruining an otherwise fine car, in my opinion. I think the car is better liked in Europe though where the engine is dealt with more routinely. The nicest of all 7-series are the 780 turbos, hold off for one of those.