As a one time SAAB enthusiast (pre-GM) I have done many jobs on these cars.

I realise that your vehicle is a GM product, but I'm unsure which engine a '99 SAAB-badged GM would have had - I abandoned SAAB completely when GM swaggered in.

If your vehicle has a derivative of the SAAB "H" type engine, having done this job in the past, I can advise that head removal is straightforward and made easy by SAAB's use of high quality fasteners and components. For instance, the downpipe nuts on my car were solid stainless steel and unscrewed easily from the rusty manifold studs. GM accountants would never have condoned this, of course...

To prevent the timimg chain from falling off the lower sprocket, I wrapped a car sponge in a polythene bag, and placed this in the centre of the chain run before removing the camshaft sprockets. A cable tie around the chain above the sponge then kept the chain in position until re-assembly.

The Swedish engines are a pleasure to work on.

659.

They used Ford engines at one time too-in fact,many of their rally sucesses were with Ford engines.

Didn't they suffer porous head and manifold water leak problems around that time?

Either would give similar symptoms to a failed head gasket. A sniff test may be worthwhile to prevent wasting time.