So I put on the new Kubota head and it went very smooth. When I started the engine it ran very rough as expected, so I bled the lines at the injectors and still found it ran very rough. I had noticed that the fuel hand pump was leaking, so I guessed that maybe it was causing air to enter. I bought a new pump and put on a new fuel filter and tried bleading again. I am able to get good pressure and engine draw down when I blead cylinders 1.3, & 4, but number 2 doesn't release hardly any fuel. I pulled the 2 line off and blew it out just for yuks, but nothing improved. When an unrelated problem pops up during a repair, it always is the worst because we can never be sure if it's related or not. Does anyone have any ideas of what could be going on here? The machine overheated prior to bringing it into the shop, but ran fine.