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 dining 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 modifications, 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 aftermarket 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-lookin' 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'll 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 zshorter 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.
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. | 
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. | 
The boxing plates basically butt up against the shock crossmember, and the axle centerline is marked. |
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. | 
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. | 
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. |