Not a bad price for that car, looks to have an Olds 350 or 403 in it. I never realized that Buicks also had Olds engines in the 77-79 models years, I was aware of them using Pontiac 301's. It makes sense as the BB Buicks were gone after 76, and if your customer wanted a larger than 350 ci engine you would be forced to put in either a Olds, Pontiac, or Chevy. I would have guessed they would have gone with a Pontiac 400 in 77 & 78 due to the use of its little brother 301 as the base V-8. But apparently I would have been wrong.
as it appears that the original small block as-built is still in the car - i believe the fact that its blue means it has to be a 403. Olds 350s were (historically) gold - they eventually stopped painting them any color but black, but I don't think they ever painted a 350 blue
Looks like a clean low mileage wagon. If it had a hitch and towing package I'd be tempted. As for the Chevy 350, in 1977 GM changed to the blue. I had a 1977 Corvette with a blue detuned 350. So hard to say what's in this one.
I am no expert on Olds engines or the colors they were painted. But all the on line info I can find has the 64-72 Olds 350's as Gold, and the 73 and later engines all listed as Metallic Blue. Also one of the reactions to the engine type law suit was to paint all the different engine types the same color so it was harder for the average consumer to tell the difference. If they looked under the hood of all the Cutlasses on the lot the engine would be the same color of blue if it was a Chevy, Buick, Olds, or Pontiac. I do remember seeing a lot of Gold and a few Red Olds engines, but according to the same sources only has a couple of years 425's as being painted Red. So who knows. You are probably correct in it being a 403, I would imagine only CA got Olds 350's. BTW the Oil Filler up front and the A/C compressor on the passenger side definatly make this one an Olds Engine.
The AC compressor is unplugged and the heater core is bypassed. Needs paint and woodgrain, correct tires..$1500 car IMO.