For those that may wish to follow the example of this build with their own, where the Dakota clip was welded on top of the original 57 frame is likely the reason the finished product now sits too low. Its more work, and more difficult, but if the Dakota clip would have been welded to the 57 frame with top of the 57 frame welded at 1/2 the height from the top of the Dakota frame, the ride height would probably been correct.

As is, the Dakota crossmember is raised up from the 57 frame too much because the Dakota was welded on top of the 57 frame. I don't know what the height (top to bottom) the 57 frame is, but lets assume that it is 4" high, measured between the top and the bottom of the frame.

If the Dakota frame was sunk into the 57 frame at 1/2 the 57 frame thickness (in our case 2") you would have raised the front of the 57 frame up 2" higher in the air then it is currently.

The body sits on top of the rear section of the frame. The suspension attaches to the front frame. When you want to determine ride height, you need to make your measurements from either the top of both sections, or from the bottom of both sections. Measuring from the top of one and the bottom of the other will result in something either being too high or too low. Its best to make these measurements while the vehicle weight and the motor weight is still on the frame sections. If the front frame section is 6" off the ground, measured from the top of the frame with the motor weight there, at the cut location, and the height o the top of the rear section of the frame is 6" to the top of the frame with the weight of the vehicle on it, at the cut location, when you splice to two sections together, you need to maintain the two height measurements to maintain the same vehicle ride height.

If you want to lower the vehicle ride height, you can rise the front section the amount you want to lower the the vehicle. That means that if you want to lower the front of the car 2", you will raise the front section 2" higher then your beginning measurements. Use caution here, this will be the actual height change at the weld joint, everything else will have to be adjusted accordingly, and any change in the equipment from the original equipment present at the time of measurement will alter the changes you are making.

In this case, he determined the front ride height from the bottom of the front crossmember, and from the top of the rear frame. Its easy to do. Had he taken both measurements from the top, he would probably have seen the 4" (or whatever the 57 frame height is) difference and thought it might be too much. Generally speaking, a 2" difference between the two measurements is a big difference on the ride height.
I sure hope this makes sense, sometimes things are lost in the translation. Gene