i dropped the upper a arm mounting holes, 1 inch down and 1/8 inch back for 65-66 . simply one inch down for 67-70, you do not have to fill in the upper holes . start with a small bit so the holes don't wander off your mark then go to the larger bit . the a arm slides right in . there is a bit of flange around the holes inside the engine compartment that will have to be flattened so the nut will pull down. i also tack welded the hood hinge nuts in place ,they tend to spin in the apron .