Hi kronustor, welcome to mightyram. Most decent head recon shops can handle welding up a crack or 2 unless they are just too far gone. Always tricky with getting stuff from a wrecking yard. You won't know what a head will be like until you separate it from a block. If you can get the cam to turn over with the rocker cover off, check to see if there are any issues with the rockers or valves. Your block will be safe as the only component in the bottom end that spins is the crank. Word of caution - make sure you replace the balance shaft bearings too. If the bottom end bearings have lunched themselves, small fragments of bearing material will have found their way through all the oil galleries (check the condition of the balance shafts when you pull them out) Don't take short cuts with putting it back together! You could get away with a replacement crank and a clean head but make sure the block is thoroughly cleaned and replace all the bearings, timing chains and guides. Good luck!