Interestin.

Ok so carbon buildup would be evident then oven cleaner should take care of that.
Aside from that, It would probably be easier to drop in a new block, if compression psi weren't any better from a new HG, than to change rings. Or are people exagerating the difficulty of such an endeavor?

 

Not sure where to get a new block? Volvo? seems expensive. If you mean a new 100k miles junk yard engine then, to me all the work to fix the one you know seems like a much better option. As they say better with the devil you know than the devil you don't.

And it's not that difficult and you get the opportunity to see things from the inside out and understand more about why it's such a great engine.