As i sit here writing I find myself crafting a character in which I change the name by which i refer to him as (first name or last), this is usually in correlation to the time period of the chapter, first name used for past events, last for current. What do you guys think of this, could this arise as too confusing for the reader?
As long as you clearly state his full name somewhere near the beginning then I don't think it would cause too much confusion.
There are better ways to show time shifts. Using his first name in one place and last name in another is not a good way to do it, IMO. Of course, if his name in the past was A and he changed it to B, then that would be fine. But think about how you can use your actual writing to depict different time periods. That would be a much better route to take.
Changing names may go along with shifts in time, but as an indicatro af a time shift? I think it is unlikely to be a clear enough signal. Not impossible, but unlikely.
I think this is something that, if done well, could work really well as part of the character arc. If the name being used is indicative of who he is and how others view him then it could be really effective. If it is just to mark which time frame you're in though it seems a little redundant.