Yes you can, although it is not technically recommended as it puts added stress on the headtube and it will slightly change the geometry of the bike itself. Since the bullit has a fairly steep headtube angle to start with, I don't think you are doing it much harm by putting an 8" fork on and slacking it out a few degrees.
to be honest, i dont think it would make more than 1 degrees difference. its designed for a 7 in freeride fork so adding one more inch of travel = about one more inch axle to crown = 1 more degree slacker. nothing to stress.