Just FYI, I hope he has a hefty tig welder. One of the gas cooled 175 amp units isnt going to work for you, you have to have some decent penetration when welding the block onto the back of the head, and adding aluminum to the head takes a shitload of amps.
You also have to machine some parts out, like the pulley spacers and whatnot, and build things like an intake and exhaust manifold(turbo), what you planning for engine management?
IMO, the volvo head swap isnt worth it if your just going to keep it N/A.