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Remember when a 15"X 8" wheel and a 9" wide tire were considered "big" on the back of your classic? These days, if you don't have at least a 17'' or larger wheel and a 10" to 13" wide tire, you might as well stay at home! With the leaf springs in the stock location, the widest wheel that can be used is an 8". By installing the CCI leaf spring relocation kit, PIN 21-131, the leaf springs are relocated inside frame rails and up to a 9" wide wheel can be used with the stock fender wells and trunk tubs. To go to the next level, the rear trunk tubs can be moved in even with the frame rails (mini tub) and up to a 12" wide wheel may then be used! In this article we will relocate the rear inner trunk tubs, install the new shock relocation bar for lowered cars and install the new double adjustable traction bars

Parts List
1955-1957 Chevy Rear Spring Pocket Kit to add bigger wheels and tires
1955-57 Rear Shock Location Kit For Standard Height Or Lowered Cars 2-Piece Frame
1955-57 Rear Shock Relocation Kit For Standard Height Or Lowered Cars 1-Piece Frame
1955-57 Traction Bar Kit Use With Rear Sping Pocket Kit
955-57 KYB Gas Rear Shock Absorber
1955-57 Non-Wagon Spare Tire Well Delete Panel

Tools Needed:
Metal Shears Ratchet
Assorted Sockets & Wrenches

Time Frame
16 Hours

Image #1: With the rear leaf springs in the stock location an 8" wide wheel with a 255· 60R tire is really the biggest tire and wheel combination you can put under the car.

Image #2: By dropping a plumb bob from the inner lip of the inner trunk tub down to the top of the leaf spring you can see that the leaf spring protrudes into the wheel well 7/8". By relocating the leaf springs parallel with the frame, this 7/8" is gained back so you can use up to a 9" wide wheel with plenty of clearance.

Image #3: To install P/N 57-133228-1, Spring Pocket Kit, the rear end will need to be removed. Make sure the car is on safe jack stands or a lift and is supported in front of the forward leaf spring eye mount. Disconnect the driveshaft, rear emergency brake cables and the rear brake hose. Next remove the two rear shock absorbers. The rear end housing is held to the leaf springs with U-bolts and shock plates. Remove the 3/4" nuts, shock plates and U-bolts.

Image #4: The front of the leaf springs mount to the frame with a sheet metal spring-eye bracket welded to the frame. The rear of the leaf spring has a shackle mount bracket that is either welded or riveted to the frame

Image #5: Remove the forward spring eye bolt and drop the front of the leaf spring out of the bracket. Make sure to save the front spring eye bolts and nuts as they will be reused.

Image #6: At the rear, remove two shackle nuts and the outer shackle plate. This will allow the spring to be removed from the frame.

Image #7: Using a torch or an air chisel and grinder, remove the forward spring hanger from the frame.

Image #8: Our frame had the rear shackle bracket riveted in place. Using a torch, we cut the heads off the rivets and removed the bracket. There were two rivets on the side of the frame and two on the top.

Image #9: There are two forward holes in the new spring pocket. The lower hole is for 2-piece frames and the upper hole is for I-piece frames. We have installed the factory front spring eye bolt into the lower hole of the pocket with a standard 1/2" washer under the head of the bolt. This will help align the pocket with the factory hole in the frame.

Image #10: Hold the pocket on the outside of the frame and align the 1/2" washer with the factory hole in the frame where the front spring eye bolt passed through.

Image #11: Mark the frame where the pocket is going to be welded in.

Image #12: We have found a safe and simple way to make sure we don't cut too much out of the frame for the spring pocket. Make a paper template, lay it on the bottom of the frame and mark the frame.

Image #13: Using a cut-off wheel or plasma cutter, cut the bottom of the frame where the spring pocket will be welded in. Make sure to leave plenty of frame in place for grinding to make a precise fit.

Image #14: Install the spring pocket into the frame and check the fit. With the spring pocket properly fitted in the frame, clamp the pocket into place.

Image #15: When the new forward spring eye bolt hole in the spring pocket is lined up with the original spring eye bolt hole in the frame, it may be necessary to trim the pocket slightly to match the frame..

Image #16: Completely weld around the outer perimeter of the spring pocket to the frame. Be sure to achieve a good "hot" weld as this is very important for strength.

Image #17: The upper rear shackle bracket welds to the top of the frame. Meas ure from the rear of the frame forward 15" and mark the frame. This will be the center line for the upper shackle bracket.

Image #18: Place the upper shackle bracket on top of the frame so that the center of the hole for the upper shackle bushings lines up with the mark on the frame. Tack weld the bracket to the top of the frame.

Image #19: The section of the frame just under the new upper shackle mount will need to be notched so the new shackle notch plate can be installed. This plate is supplied to box the frame in and add strength. Center the plate with the upper shackle mount and mark the frame where it will need to be cut. Make sure there is 1-1/4" (vertical) of stock frame left between the top of the new frame channel and the top of the frame.

Image #20: After marking the outside of the frame, use a square to transfer the marks to the bottom and inside of the frame.

Image #21: Use a plasma cutter or cut-off wheel to notch the frame for the new channel.

Image #22: Fit the new channel into the frame and weld it into place. Again, a good "hot" weld is required for maximum strength.

Image #23: The stock leaf springs or lowering springs will work with the new spring pocket kit. We are going to install new standard height 5-leaf springs P/N 57-133302-1 . The front leaf spring-eye fits into the new forward spring pocket. The rear spring-eye attaches to the new shackle and bushings included in the kit.

Image #24: With the leaf springs now moved in parallel with the frame rails, the spring perches on the rear end housing will need to be moved inward to match the leaf spring width. Before removing the old spring perches, the original pinion angle must be determined. Place the rear end on a set of jack stands or saw horses and using an angle finder check and record the pinion angle.

Image #25: The factory spring perches were spot welded to the rear end housing. Use a torch or plasma cutter to remove the perches.

Image #26: To determine the location of the new spring perches included in the kit, measure from side to side on the leaf spring center pins.

Image #27: Place the new spring perches and rear end housing on the jack stands and set the pinion angle. Make sure the left and right perches have the same measurement from each axle flange. This will place the rear end in the exact center of the frame.

Image #28: With the pinion angle set and the perches in the proper location tack weld them into place. Next turn the rear end over and weld the spring perches solid to the rear end housing.

Image #29: Set the rear end back onto the leaf springs. Using the stock U-bolts, nuts and lower shock plates bolt the rear end into place.

Image #30: With the leaf springs relocated, up to a 9" wheel may now be used. We are going to go that extra step and move the inner trunk tubs inboard even with the frame rails. This will allow up to a 12" wide wheel and 13" wide tire to be used!

Image #31: The inner trunk tubs can be moved in (viewed here from underneath) 3" per side; even with the frame for more tire clearance.

Image #32: The section of the trunk tub that will be moved will be from the inner trunk wall to 3" inboard from where the wheel well attaches to the trunk wall, floor and under the seat pan.

Image #33: The trunk hinge boxes have a plate on the bottom that is welded to the top of the tubs. Using a saw, cut the plate leaving a lip on the bottom of the box. Then drill out the spot welds that secure the hinge box bracket to the tub.

Image #34: Mark the trunk tub and floor where the cuts will be made . Measure in from the trunk wall 1". Mark the trunk floor 3" inboard of the tub. This will allow the factory tub to trunk floor seam to be reused. This will save a lot of work and will look nice and clean.

Image #35: Using a cut-off wheel or saws-all cut around the entire trunk tub. The support from the package tray to the under the seat floor pan will need to be cut also.

Image #36: Once everything is cut loose the trunk tub can be removed. All of the raw edges will need to be cleaned up with your grinder before welding.

Image #37: Place the cut tub and trunk floor in place. This will put the inner lip of the tub even with the frame rail underneath. Now mark the trunk floor where it needs to be cut.

Image #38: Using a cut-off wheel, cut the trunk floor . Place the cut section of tub and trunk floor in place and tack weld.

Image #39: If the fit is satisfactory, weld the relocated floor to the original floor pan. After the floor is solidly welded in, weld the l" lip you left on the bottom of the hinge box to the top of the tub.

Image #40: Using a piece of cardboard, mark the opening between the stock outer trunk wall and the relocated inner tub.

Image #41: Using the cardboard as a pattern , trace it out on a piece of 16-gauge sheet metal. Use a pair of metal shears to cut out the filler panel.

Image #42: Once the fit of the filler panel is satisfactory, weld the entire panel into place.

Image #43: With the filler panel welded into place the rear package support may be welded back into place.

Image #44: With the tubs moved in even with the frame there will be enough room to use up to a 12" wide wheel. We have . also installed our new spare tire well delete panel P/N 57-154085-1

Image #45: We also installed the new shock bar for the lowered cars and two-piece frames, PIN 57-161066-1 and the new double adjustable traction bar kit, PIN 57-133262-1 for the spring pocket kit along with the KYB gas charged rear shocks, PIN 57-133321-1. The rear end is now really tied into this car nicely and should give great traction and handling characteristics.

Image #46: We decided to use the popular polished American Torque Thrust wheels in 17'' X 9-1/2" with 6-1/2" back spacing. The 6-1/2" back spacing indicates how much wheel there is from the axle face of the wheel inward. By using a wheel with a 6-1/2" back spacing the stock length rear end may still be used! This wheel makes this upgrade very economical since no rear end or axle mods are needed. You can use up to a 9-1/2" wheel without narrowing the rear end. Anything wider will require a narrowed rear end housing such as a 9-inch Ford. The front wheel we chose is a 17" X 7" with 4" back spacing. The 4" back spacing works perfectly on the front of a '55·'57 with disc or drum brakes

Image #47: There is nothing like a set of wheels and tires to change the whole look of a car!