Moog Offset K7103 installation question -'65 Barracuda

If the arrows are not perfectly in the horizontal plane, it will effect the angle of the arc of the upper arm as it swings up and down, but the discrepancy shouldn't be very much unless you really got them in crooked. "Eyeball" horizontal should be good enough. I wouldn't worry about re-pressing them — after the bolts are tightened down they aren't going anywhere.