It's important to pay close attention to the radiator core mounting points, as these will locate the stub as well as the front sheetmetal. If these points are off, you may not be able to bolt the fenders and hood back on the car properly, creating much more work later on. In other words, double-check this area several times.

For this application, the directions had us mark the frame cutoff points 14 3/4 inches from the center of the front body mount bolts on each side of the car. We scribed a square line on each side of the frame to help keep the cuts straight, and used a reciprocating saw for a clean cut.

Before getting to the next step, we first had to address the inner walls of our frame. The Pontiac's frame had stamped openings that protruded inside the 'rails (arrows). We had to trim these areas in order to properly weld on the internal gussets from the stub kit.

There were two 1/8-inch gussets to weld to the frame, and two for the stub....

...These were tack welded on opposite sides of the frame and the stub so that they formed a slip joint.

Fatman allowed for a 1/4-inch weld gap at the joint when the stub was placed in the proper position. You can check this position by using the radiator core support points you previously marked on the floor.

Before tacking the stub to the frame, make sure the radiator core support is at the same height as the original, using the measurements recorded earlier. Our stub literally fell into place with only minor adjustments needed to line up properly.

With all measurements and mounting points checked and rechecked, we tacked the stub in place at the joints. Then we rechecked measurements just to be sure.

It's a good idea to trial-fit the fenders and core support to make sure they not only line up to the body correctly, but that the wheels are positioned within the wheel openings to your liking.