What can I do about my arrows hitting 4 inches left. My set up is 27.5 inch draw,pse 300 arrows, 100 grain points and a quick tune rest. drawing 67lbs

From the information you gave which isn't much, I'd say adjust your sight.

Do they consistently hit left as you increase the yardage? If you get good flight, just adjust the sight.

If not, your rest may need adjustment, or some other factor may be coming into play, such as vane clearance.

Is this a new problem since switching to a new arrow, or bhead, or something else?