Pretty much anything can be brought back from near death, but that looks rather nasty.

It also looks like it'll expensive to get back to tip top condition.

If the valves are hammered get new ones. Buy the whole assy including collets, springs, seals etc 'cos they're probably all shot to bits. The seats will definitely need cutting. This is always a good idea even on a new bike. If the cutting is done correctly then you don't even need to lap the valves in, but you will need to check that they seal.

If the pistons are toast (highly likely) then there's a chance that the bores are smoked too. So that's gonna be a bunch more dosh.

While it's open you may as well fit new shells to the rods and crank.

Anyone keeping score here?

In a nutshell I'd hoss the lot in the biffa and invest what I would've spent on another stroker.

But that doesn't teach you anything, so keep soldiering on old boy, it'll come good in the end.