I have a 65 valiant with a 170 slant and i'm have idling problems in gear.
I have checked the manifold bolts and made sure they were all snug, vacuum lines, made sure the carb is tightened down,and set the carburetor up. It idles nice and smooth in park, but ingear it idles really rough. Could this maybe be something to do with fuel delivery (fuel pump)? the only thing that i haven't checked is the timing, but the engine was retimed a year ago? any suggestions on things to check or do would be very helpful

I would definitly check the timing. I would also replace the points (if you still have them) and adjust the dwell to specks. (I thing point gap is .019 to .021, cant remember the dwell setting). Also, if you never had, now would be a good time to adjust the valves to speck. .010" for intake and .020" for exhaust. Easy process, just ask if you don't know how.