Stick welding aluminum

[jwmorris]

The adjacent bolt holes won't give you better alignment that the dowel pins in the block (one is right next to the mangled hole). If they were not in place the head could move around due to clearance between the holes in the head and studs/bolts, if the fastener is 1/2" the hole in the head will be somewhat larger than that. Turn a bar that is a good fit into the bolt hole in the head and drill down the center with what ever bit you intend to use, makes for a cheap bushing and will be fine for the one time use.