I have a head from a 230S and it needs a bit of metal welded into a combustion chamber and around a couple of coolant holes. I have a very good welder but he wants to be sure to use the right filler material. He looked up filler rods or Mig wire and his info told him to use 4145 aluminum.

Anyone have a recommendation or used a particular sort of wire or rod that gave good results? I want to get this right the first time.