MBHD : Yepp Your are absolutely right,the engine is a B21 that was found in the 240 models 1975-1977 it's a 2.1 liter OHC engine that originally had a 8 valve head (but the heads are intercangeable between the various models so this engine has a 16 valve from a newer engine),after that the B23 (2.3 liter)came and hanged on for almost a decade.
After that the B230 came along ,it's the same volume as the B23 but had some internal changes such as narroved main and rod-bearings to reduce friction.
But old school or not it's still a cool engine in my book and still a small fourbanger inline that scares the living daylight out of the V8 cars,and thats what counts in the long run.
LGriffin : The head is a 16 valve head out of a 740 model (86-90 something) and is still available today as a sparepart at the Volvo-dealers,this one is pretty heavily modified,they welded the combustion-chamber and grinded it to fit their need,they also had the spark-plugs sunken deeper into the chamber and the sprockets for the camshaft-drive is hand made by the owner/builders and is adjustable.
And there's a ton of other oneoffs on that engine: Intake is homebuilt and is made of carbonfibre it has 4 56 mm butterflyes and four 1800cc injectors,the exhaust-manifold is also home-made in stainless steel wastegate is also built by owner and a other guy who is a true pro on turbo-charging here in Sweden.He's the guy who had the Turbo put together to fit this engine.
The boost is set on 2.65 bar (aprox. 39 psi)to reach that power of 952 hp and 835 nM of TQ.
Regards Hans "Speed-Swede"