Snapped camshaft at idle.

[745 TurboGreasel]

I'd be worried if I couldn't stall the car in every gear using the brakes.

I know Volvo uses some flywheels with a flat surface, and some have a dished grind. If you use the wrong parts, or a machine shop has ground your dished flywheel flat, there isn't enough surface area, and it slips.
To me, this disc looks burnt to hell in one ring, and new in the rest?

I think I have a Sachs disc I can still read the numbers on, I'll dig that up later.

Where was the red powdered metal coming from?