1971 Volvo 145S Wagon | SwedeSpeed

The engine does appear to be previously fuel injected because you can see that plugs have been inserted into the head where the injectors were fitted. If the engine is a 1971 it will be a B20E with a 10.5:1 CR and definitely needs 92 octane fuel. However, I did not think that fuel injection was an option on the 145 in 1971. The ‘tell’ would be the badge on the front fender. If it says 145S then it was carb (twin SU or stromberg) equipped. A hypothetical fuel injected car would have 145E (E for einspritzen). That leaves the engine as a transplant as you suggest and it could be a 1971 B20E with 10.5:1 CR or the later B20F with 8.5:1 CR. Theoretically the B20F can live with lower octane fuel; but, the very deep quench band on the B20F reduces the quench effect making the engine more prone to detonation than modern engines so net effect is that it probably still needs something better than 87 octane fuel.

Your car has a 4:1 header which is non stock which means that there will be some fabrication to match up it up to a ‘stock’ exhaust system. This is the exhaust system as fitted to the B20E engine cars

It is slightly larger diameter piping and has a resonator and fits the 2, 4 and 5 door versions. Still available; but, on back order because they do limited production runs
Exhaust system 140GL/E 70-73 | Exhaust system 140 GL/GLE 1970-7

These are the exhaust systems for the non injected cars
Exhaust system 140 1967-73 B18/B20 A/B/D | VP Autoparts

Give VP Auto a call to find out what the difference is.

What might work is this which is a 1/2 kit meant for use with a 4:1 header. Will still probably require some modification to match up to the header. However, the mufflers look kind of small so it may be just as noisy as what you have
Exhaust system 140 2,5sport half kit | |
Your tail pipe is exiting in the correct location in the last photo.

Odd combination of switches on the left hand side of the dash cluster. Normally there would be Windshield wiper, choke (if carb equipped), headlights and heated rear window switch below those three. As you say, clearly someone’s project car.

My friend had a 1970 145 and it did have the factory supplied optional roof rack and it was mounted through the roof with screws and the 6 pads for the screw mounted pedestals are in approximately the same location as in your photo, so yes, it might have been a factory supplied rack.

I like wagons. I had a 745 turbo for 25+ years and it was my wife’s favorite car. B230FT had lots of zoom compared to the early ’80s Toyota Corolla she had before we got married. The Volvo dealer up and left town so now I have a 2021 A4 Allroad which has a lot more zoom, gets better fuel consumption and is much quieter; but, can’t carry anywhere as much stuff as the 745 and there is generally not a hope in hell of me fixing anything complicated on the car because I lack access to the Odis diagnostic system. Also, Audi has an infatuation with TTY fasteners all over the car (not just head bolts) which is an additional expense when it comes time to do repairs. The Audi service manual that I have is multiple thousands of pages long. I did OK with the Haynes service manual for the 745 which was decidedly less than 1000 pages long.