If it's an older vehicle probably wear and tear from old age. If it is a newer vehicle probably from abuse.
You need to unbolt the motor mount that is in the way, lift the engine with a jack just high enough to slip the old belt out and new belt in between the mount and engine, reroute the new belt, lower and connect the engine back to the mount,
YES, IT COULD BE BROKEN.
Timing is off. You may need a new timing belt.
The year, make, model and engine wasn't mentioned but in general you remove the motor mount anchor bolt(s), lift the engine a few inches and support it safely, unbolt motor mount(s) from engine, remove mount(s), replace mount(s) and finish in reverse order.
you can bolt the engine in place with motor plates and then you will probably need to make a new cross member for the 727 transmission to mount and of course you will have to have a new drive shaft made.
Front of the engine, behind the engine mount.
Loosen the engine mount retaining bolt. Jack up your 2000 Monte Carlo engine. Remove the engine retaining bolt and the engine mount bushing. Put the new engine mount bushing in and reverse the process.
check your engine mounts..I am not sure where they are but if you can move the engine with a prybar you need new mounts..they arent to expensive
To change the engine mount on a Volvo, first, ensure the vehicle is securely lifted and supported. Locate the engine mount, which is typically situated between the engine and the chassis. Remove any bolts securing the mount to the engine and chassis, then carefully lift the engine slightly using a jack to relieve pressure on the mount. Replace the old mount with the new one, reattach all bolts, and ensure everything is tightened before lowering the engine back into position.
Bad piston rings. Get new engine.
Follow the Youtube instructions.
It has been a while but from what I remember you need to put a floor jack under the motor and pull the bolts from the upper engine mount. Lift the engine enough to slip the new belt passed the mount and install on the pulleys. Fricken engineers!!