Knocking I had a push rod that was out of place and the rocker arm?

I had a push rod that was out of place and the rocker arm it was on cracked. I replaced the rocker arm and shaft because a few of the arms locked up. After I got everything back in I test drove it and I heard a knock and I'm not sure what's causing the problem I have not checked the oil pressure yet or the timing but those are the only things I can think of that would cause to problem and I have new oil in it and at the right level.