Damage to heads

Just purchased a 1976 KZ900. Seller said everything had just been gone through and no issue. Now I am finding multiple problems so shame on me for taking some ones word and not investigating from top to bottom. Anyway its mine now to fix and get running.
1st issue: While working to remove the heads the tach gear needs to removed. Unfortunately the previous owner ( most likely due to leaking and his laziness) used some type of sealant between the case and the cable entrance. During my attempts to remove the gear the case was damaged (see pics). Is there anyway to repair this or is the head just trash now? Thanks in advance for your help

That can be welded and drilled. You can reshape the outside. IF IT TAKES FORCE, STOP. You could have heated it up with a propane torch. :whistle: Any more problems, PLEASE ask us.
Steve