As I mentioned to you a while back, I love the B-18, what a robust and wonderful iron beast it is. Solid lifter, OHV, gear drive (no chain), huge bearing surfaces. I had a PV-544 Sport (egg on wheels, similar to the 1946 Ford) and I hot rodded it with parts from IPD here in the USA, a performance house specializing in Volvos (still exists in that role today too). Hot cam, ported and polished cylinder head, big carbs from an Austin Healey 3000, headers, the works! That thing was geared so low it would barely reach 100 but it sure would pull in the lower speed ranges and easily rev past 6000 rpm.

I raced it around when street racing was a little more socially acceptable, and I always enjoyed surprising people with the unbelievable power it had with that stump puller of a low gear. Ha! Great snow car too, especially with a load of concrete blocks in the trunk.
At the time I had a buddy with a Cortina GT with the special crossflow head. It was a nice cross-country ralley car, and it handled better than the Volvo. However, on acceleration my 544 would eat that car alive. He always wondered why.
I still have a spare block and cylinder head holding up one end of my shop. Those parts have so much iron in them, I think I recall the block could be bored out to 2000 cc. I have an intake manifold with dual SU carbs too, lol.
They are very simple motors, very strong, easily worked on, and they would make a great boat motor. As one of my friends said, the good thing about a Volvo is they last forever, and the bad thing about a Volvo is they last forever. I've had 6 of them, still have two. They're great cars.
Porsche helped design the 4-valve cylinder heads that came out in the late 1980s, and I have one of those on a 740 GLE 16V which is my old standby. It's pretty remarkable too, lots of high end power, not much torque, but very happy on the interstate.
The B-18, however, is the motor that established Volvo's reputation in the United States for being so durable. Mine was a 1963 model, and the marketing byline for that year was "drive it like you hate it". When I bought my PV-544 Sport, I asked the engineer who sold it to me how many miles it had on it. He said, Ohhh, about 300,000. Nobody knew for sure. I hot rodded it, ran the daylights out of it, and sold it for 3X what I paid for it, and never broke anything on the car. When I sold it, the car had new paint, new upholstery, CN36 Pirelli tires just like the turbo Porsche of the day, and it ran like a sewing machine until you stepped on the gas, and then it would howl. I actually towed a 17' Chris Craft Sportsman with it on numerous occasions too. Bachelor life was fun, heh heh.
Now my wife wants one. We've been looking casually, and guess what? The price has skyrocketed. I think she needs to stick with her XC-90. That will be our tow vehicle with the Sea Skiff, and the 740 will also do some towing too.
Got to love those Volvos ! My mom and dad have a V-70 like yours
Regards, Paul