Let's face it, your truck's cargo hauling days are most likely over. Now that you've come to grips with it you might as well do something to make it handle like some of the other two-seaters on the road. What better way to make it handle like a sports car than to use the suspension from one of America's premium sports cars, the Corvette?
One such company to embrace Vette suspensions is Flat Out Engineering. They offer kits to install '84-87 and '88-95 front and rear Corvette suspensions in '49-59 Chevy pickups and '41-64 Ford pickups. We went out to Bobco and followed along as Mike Briggs was upgrading a '56 chassis with '87 Vette pieces. We originally set aside two days to do the front and rear but once Mike got going the frame was rolling again with independent suspension on both ends in less than seven hours. This not only says a lot about the work done at Bobco but for the ease of installation using the Flat Out Engineering kits. This month we'll cover the front install and finish the rear in next month's issue.
Flat Out has designed the crossmember with all the correct geometry to install the Corvette control arms, rack-and-pinion steering, sway bar, and coilover shocks to provide superior cornering, handling, and allow proper frontend alignment. All that is required are a few careful measurements to locate the crossmember correctly on your chassis. Once the stock '84-87 Corvette suspension is installed any competent wheel alignment shop can align it using the factory specs.
Bobco did the install starting with a bare frame but there's no reason it couldn't be done with the cab still mounted and the front sheetmetal and bed removed. If you're starting with a bare frame it would be best to sandblast it to obtain good clean metal surfaces for proper installation and welding.
If you're starting with an assembled truck you might be a step ahead. To achieve the "Right Look" it is important to end up with the wheels centered in the wheelwells after the installation. Stand back and look at the stock wheels in the wheelwell and determine if you like the way that it looks. Next imagine what that will look like with the finished wheel and tire size, (height, diameter, etc.). Keep in mind that the truck will be considerably lower.
If you can't visualize this, you can cut out a piece of cardboard to the diameter of the tires you are going to run and place it inside the wheelwell and see how that looks. Once you have determined that this look is to your satisfaction, mark the axle centerline on the framerail, straight up and down from the bottom to the top of the rail. To determine your axle centerline, use the center of your new wheel, (or cardboard pattern if that is what you are using) as your new center.
If you're still not sure you want to use the Vette stuff because you think the cost might be too high to go with such high-tech parts, you might be surprised at just how much you can pick up complete front and rear suspensions for. Chances are pretty good that once you factor in the cost of rebuilding an old 9-inch and then the cost of a four-bar set-up you just might come out ahead.
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 The front crossmember comes...  The front crossmember comes fully welded as a unit along with separate upper shock mounts, boxing plates, and the necessary hardware. |
 We are installing '87 Corvette...  We are installing '87 Corvette pieces but kits are available to use suspensions up to '95. Be sure to get the entire suspension assembly because almost everything is going to be reused. A company like J&D Corvette will have everything you'll need. |
 Before we started anything...  Before we started anything we made sure that the frame was square and had not been tweaked or bent out of shape. Mike and Bob measured side to side, front to rear on both sides, and in an X, from one side to the other from
several different locations using crossmembers and rivets as reference points. If your frame is more than 1/8-inch out of square, the frame should be
properly straightened before proceeding. |
 Before removing the original...  Before removing the original suspension, scribe a vertical line on the frame to locate the stock axle centerline. Using the axle snubber holes as a reference point isn't recommend, as these holes can vary as much as 1 inch from true center. It is important that the front wheel visually looks centered in the wheelwell, especially on '53-56 Ford pickups, the front wheel was too far to rear to properly center it in the fender opening, and lowering only exaggerates this situation. In this frame's case the snubber hole was centerline. |
 Flat Out Engineering recommends...  Flat Out Engineering recommends moving the front axle centerline 1 to 2 inches forward from the stock centerline depending on the wheel and tire diameter used. If the cab is still mounted on the frame, hang the front sheetmetal and mock-up the wheel and tire combo to determine the proper front-axle centerline location. Mark this location on the framerail. Mike moved the centerline forward 1 1/2 inches. |
 It was now time to get the...  It was now time to get the boxing plates ready to be tack-welded. Since the edge of the upper and lower framerails were not straight Mike used a straight edges to mark the rails to allow the boxing plates to fit flat. |
 Using a plasma cutter and...  Using a plasma cutter and then a grinder Mike got the edge straight enough to fit the plates. The boxing plate should be slightly shorter in height than the framerail surface so that you are filling in a small "L" shaped weld surface at both top and bottom. If the boxing plate is the same height as the frame rail, you are not getting the proper weld fill, and you will grind most of the strength away when you do your finish grinding. If the top or bottom rails are not 90 degrees to the sides of the rails, tap them up or down as necessary, or grind a little off of the boxing plates to allow this proper fit for welding. |
 Mike placed the boxing plates...  Mike placed the boxing plates on the inside of the framerails and tack welded them. You don't want to weld them solid at this time. It's better to wait until you determine the final correct
location of the new crossmember. |
 The Corvette front spindle...  The Corvette front spindle center is 5/16 inch behind the ball joint and spindle upright center. That means the center of the wheel is 5/16 inch to the rear of the center of the new crossmember. So the spindle (not the crossmember centerline) will locate on the frame centerline (vertical line you scribed on your framerail). The easiest way to do this is to mark a vertical line on the center of the upright portion of the new front crossmember on each side and then mark another vertical line on the crossmember upright 5/16 inch to the rear of the crossmember centerline. This is your spindle centerline or the center of the wheel when installed. |
 Mike slid the crossmember...  Mike slid the crossmember up from underneath the frame and positioned it by lining up the spindle centerline mark (rear most line on the upright) with the framerail centerline using a small square. Make sure you get this right, it will determine haw well the wheels will look in the fender openings. |
 The crossmember should be...  The crossmember should be sitting level with the ground when the truck is at ride height. Bobco has found that with the frame sitting level the crossmember should be set approximately 2 to 3 degrees lower in rear than the front to duplicate the most common installation when using small front tires and larger rears. Most people use a 25- to 26-inch tall front tire and 28- to 29-inch tall rear tire. Measure your wheel and tire combinations and base your ride height and frame angle on that. If you're using the same size tire all around, place the crossmember level. Mike determined this angle by placing a magnetic angle finder (protractor) on the top of the center of the crossmember. |
 The front crossmember should...  The front crossmember should be level at this point and the tubular lower control arm mounts should be horizontal when the frame is at ride height. After double-checking everything again Mike tacked the crossmember in place. |
 Using the rack-and-pinion...  Using the rack-and-pinion steering unit as a guide, Mike located where to notch the framerails and boxing plates for the rack clearance. He drew a line around the outside of the C-notches provided in the kit to mark the location where to cut. |
 Mike used the plasma cutter...  Mike used the plasma cutter again to cut the framerail and boxing plate (this step would be hard to do without one). |
 Before the C-notches were...  Before the C-notches were tack-welded in place Mike test fitted the rack assembly once again. Once he was sure everything fit okay the
C-notches were welded in. |
 The leaf spring attaching...  The leaf spring attaching parts needed to be removed from the Corvette lower control arms and their mounting holes needed to be drilled out to 3/8 inch for the new lower coilover mounting brackets (if you reuse the metric bolts the holes won't need to be enlarged for the standard bolts). |
 The Corvette upper and lower...  The Corvette upper and lower control arms, and spindle uprights were installed as a unit. The lower control arm mounting rod is threaded at both ends so it had to be centered once the arm was set in place and nuts installed at each end. |
 Before Mike attached the upper...  Before Mike attached the upper arm, he needed to install the coilovers. The new mounts were bolted onto the lower coilover eyelets (the bolts will not go through once the mounts are installed in the control arms). |
 The coil and mount units were...  The coil and mount units were then bolted to the lower control arms. |
 The upper control arms were...  The upper control arms were then installed making sure to use all of the stock Corvette spacers with the tapered side toward the control arm (the thicker ones goes toward the front between the crossmember mounts and the arms). |
 With the suspension now in...  With the suspension now in place Mike was able to determine the proper position for the upper coilover mounting brackets. The coils should be vertical. The brackets were bolted to the end of the coils and placed on the outer portion of the crossmember uprights. When positioned the coil mounts extended up to (and provide a gusset for) the upper control arm mounting plates and sat on top of the top framerail. Depending on the angle you set your crossmember on, it might be necessary to grind one leg of the shock mount to allow it to set straight vertically. Once the location was determined they were tack-welded in place. |
 The rack-and-pinion unit was...  The rack-and-pinion unit was bolted in last. Make sure to get this half-round Corvette bracket as part of the assembly because it does not come in the kit. |
 With the entire suspension...  With the entire suspension bolted on Mike checked everything to be sure it was located properly and was all square and level. The suspension was then removed and the entire assembly was welded. |