Classic Performance Products 378 E Orangethorpe Ave., Placentia CA 92870

Classic Performance Products

1957-60 F-100 C-Notch Kit

By Grant Peterson
The old stink bug stance on the primered Nova or Tri-Five running 3 1/2-inch Centerlines in your high school parking lot belongs then and there, not on your classic truck. Obviously, trucks have a heavy duty utilitarian lineage, but how many guys or gals do you know who are more careful with their trucks than their mom's antique dinning table. They take pride in the fact that nothing goes into, let alone scratches, their truck's bed. That's all fine and dandy and to each his own, but what's the point of seeing blue sky between the ground and the bottom of your truck bed if you're not hauling anything. Time to get with the program. Restorations have an excuse, and we're not building hay haulers or rock crawlers here, so get your truck down to earth! Each truck necessitates its own way of going about suspension modi!ications, but it's not rocket science, and you don't need airbags to get your truck low while maintaining a decent ride quality. We have been following a '60 Ford F-100 that has been undergoing a plethora of chassis mods in order to help bring it up to today's standards without getting too wacky. last month we outlined what it takes to lower a '57-60 F- 100 with a dropped axle from Classic Performance Products in order for them to develop several kits for these Fords, which are kinda out on their own as far as after-market upgrade parts are concerned. With the frontend nice and low, attention was turned to the rear. All of the kits out there for '57-60s are actually for earlier trucks and use a shorter leaf spring in the rear, which means the spring mounts need to be moved.. which can lead to many problems, plus shorter springs don't ride as smoothly as longer ones, it's physics. One of the easiest ways to lower the rear of most trucks is to "flip" the rearend to rest on top of the leaf springs. That automatically lowers it the width of the axle tube (usually about 3 inches), plus the leaf spring pack, which varies, but let's say at least 2 inches, so that's a modest 5 inches right there! The only problem is that this usually eats most of the clearance between the bottom of the frame and the top of the relocated axle tube, which calls for a C-notch in the frame. This can be mild to wild depending on your needs, and you've probably seen trucks at shows sans a bed floor and tall Brooklyn Bridge looking notches or stepped frames so the owner can lay said truck on the ground, literally. That's not for everyone, and often a dab'll do ya. CPP's new kit comes with a C-notch package that will give roughly 2 1/2 inches of extra frame clearance, which on a lowered or custom truck, car, or hot rod is usually about all the suspension is gonna travel anyway. Luckily, CPP got together with Deaver Spring to build the new bolt-in replacement leafs that lower the truck about an inch, not to mention they'll ride smoother than worn-out and fatigued stockers with button sliders at the end of each leaf. CPP has gone to great lengths to make sure this installation goes smoothly, and even include shorter shocks that bolt into their stock locations. While all this work was going on the new Truetrac Posi third member with a 3.00:1 gear showed up and was installed into the Currie rearend while the bed was off. That Smeding Ford 392 small-block will smoke both the skins now. Obviously, with the C-notch there is a decent amount of fabrication involved that requires a certain skill level as well as tools, but even if you hire a shop to do this, it's not too complicated or time consuming. In fact, with the work being done by professionals, this was started at 8:30 a.m., and the last picture was taken by 1 :00 p.m. the same day.
So call classic Performance Products at 800-830-1724 to order everything you need to get your late-'50s Ford down on the ground! Stay tuned for more '57-60 F-100 tech.

1.Here's the first part of the new '57-60 F-100 lowering kit from Classic Performance Products (CPP) new rear shackles, shocks, and C-notch plates. The shackles even come with new hardware even though it's not in the picture, which will be a lifesaver since most of the original shackle bolts are pretty gnarly by now.

2.The new leaf springs are made for CPP by the specialists at Deaver Spring and would have been a special, time consuming, not to mention expensive job if you'd ordered a set before CPP and Deaver sat down and figured out how to put these into production.

3. I know it doesn't look like much is even left of this '60 F-100, but if you've been following the work that's been going on, you know we're starting to get somewhere. After the rearend is up to snuff, the truck can start going back together. Let's roll 'er in and get started.

4. With the rearend sitting on top of the stock leaf springs and the bed off, there's about 1 1/2 inches of clearance between the rearend and the frame, which is how we'd like it to sit with the new springs installed and the bed in place. As it is, this clearance disappears when the bed is set back on the frame. The C-notch will give us that extra 2 1/2 inches we need.

5. Prep for the C-notch boxing plates starts with a good cleaning and grinding of paint on each framerail from the shock crossmember forward about 18 inches.

6. The boxing plates basically butt up against the shock crossmember, and the axle centerline is marked.

7. With the pre-bent notch plates, find their center and match it up to the axle centerline, then trace their outline. Jeff decided to move the centerline back about a quarter of an inch since the rearend moves back slightly as the suspension is compressed.

8. CPP has a few luxuries, like a CNC plasma cutter, but you can cut the notch out of the boxing plate with the old gas axe, plasma cutter, bandsaw, or even a grinder with a cut-off wheel.

9. Just like butter! If you have jagged edges or slag from the torch, it'll be easier to grind and smooth everything now than when the plate is welded in the frame.

10. 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.

11. 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.

12. 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.

13. 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.

14. 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!

15. Finish results should look something like this, with a nice uniform weld joining the pieces together.

16. 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 smoooother ride.

17. 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.

18. 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.

19. 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.

20. 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.

21. 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-gear was installed to ensure both hides would fry!

22. 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.

23. 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.