With the notch cut out of the boxing plate, it gets tacked (or clamped) back in to make a reference for the cut on the outside and bottom of the stock framerail. | 
Once marked for placement, break the tacks, move the boxing plate to the outside of the frame, and trace your cutout for the notch. Mark it well enough so you'll be able to see it while using the torch or whatever method you'll use to cut it out. Now is a good time to remove the truck's rearend and springs. | 
The acetylene torch is still a good way to do this as long as you're careful and steady. Obviously, knowing how to use the cutting torch properly makes a difference. Don't forget safety glasses, gloves, and a hat, and keep a fire extinguisher handy. |
No matter how you choose to cut the notch, there will probably be some amount of grinding involved. Take your time and fit the bent C-notch plate into the frame nice and square; also, avoid leaving big gaps to fill with weld. | 
When it comes time to weld everything together, make sure it gets done well with at least a 220-volt MIG welder, and skip around so you don't put too much heat in one spot to minimize warpage. This is structural, so don't be afraid to ask for help! | 
Finish results should look something like this, with a nice uniform weld joining the pieces together. |
On the road to reassembly! The new leaf springs bolt right into a stock truck and feature these little sliders at the end of each leaf for a much smoother ride. | 
50 years of use and fatigue can do this to what look like normal robust leafs. This leaf isn't just cracked, it's busted, rendering it pretty much useless compared to the rest of the pack. | 
In a stock F-100 the rearend bolts to the bottom of the leaf springs, and one of the easiest ways to lower this truck or almost any truck is to "flip" the axle so it sits on top of the springs, basically lowering it 5 to 6 inches right off the bat. To locate the axle on top of the springs, the bolt that holds the leaf pack together has to be installed from the bottom since it has a special round head. Simply clamp the pack together and remove and reinstall the bolt the opposite way. |
Since the front spring mount is stationary, only the rear shackles are replaced. When doing this, make sure the top shackle bolt is installed from the inside out so its head is toward the frame to avoid any interference. | 
The beautiful thing about CPP's kit is that it allows the springs and shocks to bolt back into their original locations-no fabrication. With the truck about 6 to 7 inches lower, it just needs shorter shocks in place of the stock ones. | 
To the unsuspecting eye everything looks just like it oughtta, which is how it's supposed to be. During all of the excitement of the build and the fact that the soon-to-be-installed Ford 392-inch Smeding stroker motor is gonna be cooking out gobs of torque and horsepower, a Truetrac Posi third member with a three-O gear was installed to ensure both hides would fry! |
With the bed back on the rear end, the truck sits about 6 inches lower than it used to, and that's without the weight of the rear-mount gas tank and fuel. | 
Look how high the back of the '60 was stock, even during a hard high-speed turn under full roll! Mucho better now. | 
Here's a shot from underneath that shows the head room gained from CPP's kit. What are you waiting for? Call CPP to stop those nosebleeds. |