I would revisit the camshaft timing.
Disregard the white lines on the belt, especially if it's a Dayco belt.
Rotate the engine backwards by enough that you can slowly bring the crank into position in the correct direction and there's no slack in the belt. Then double check the marks.
Is there a chance you damaged a valve when you removed the old belt? Did the cams all spring off in every direction? Did you rotate the crank at all while the belt was off or was the belt removed at TDC rather than the halfway down the bores position? The valves can easily touch each other if you rotate the cams in the wrong dirrection and they have very small stems that bend easily. If they have bent valves they often have a characteristic valve train noise at certain R/min.