As expected, the new GM Silverado and GMC Sierra pickups have flooded the light truck market with hundreds of thousands of 1/2-ton 4x4s that need to be lifted. We've met the Chief Engineer for GM's fullsize truck line, and trust us, he's a smart guy. But until the Silverados come from the factory with 35-inch tires we're still going to have to find ways to lift these trucks. And now that these new K1500s have been around for almost five years, Explorer Pro-Comp has taken the time to research and engineer its new bolt-on kit that doesn't use costly new cast-iron spindles. Instead Explorer Pro-Comp has gone with its traditional GM IFS lift design that drops both the upper and lower A-arms 6 inches. The result is a pretty beefy lift kit that costs less than a lot of its competitors.
We headed out to Mesa, Arizona, to see Mike Boyd at Off Road Unlimited when we heard he was going to have his right-hand man Brett Corder install the new Explorer Pro-Comp 6-inch kit on their shop truck. Brett can install an IFS lift kit in his sleep, or in a driveway, but he says doing it in his sleep is easier. We have been fortunate to get to work with the best off-road shops in the country, and we jumped at the chance to have Boyd and Corder walk us through an install.
1. Corder's secret to lifting an IFS Silverado is to leave much of the suspension in place to save time and eliminate the need to lift heavy suspension components. During the install he always had the upper or lower A-arm, CV-shaft, and calipers bolted in place. The first step in installing a lift is to support the truck on a hoist and remove the torsion bars, shocks, and tie rods so you can unbolt the lower A-Arms from where they pivot in the frame. | 
2. Every GM lift kit we have ever seen requires you to cut this differential-mounting ear off of the lower crossmember. The Explorer Pro-Comp kit is no different. The instructions call for you to make this cut with the front differential removed from the truck, but Corder finds he can make a more accurate cut by leaving it in place. Again this saves steps and time, and because three other bolts hold in the front differential, there is no need to take it out of the truck. | 
3. The frame-cutting party continues by removing the factory GM upper bumpstop mounts from both the driver and passenger side (shown) of the truck. The instructions tell you to use a hole saw to cut out the welds that hold these suckers in place, but that takes forever and will ruin the best hole saws. Corder uses a Sawzall to cut it off flush with the frame and then grind down any rough spots. |
4. The premise of all IFS GM lift kits over 4 inches is to lower the mounting points for both the upper and lower A-arms. This is always done with some form of new subframe that bolts in where the lower A-arms were mounted from the factory. In the case of this Explorer Pro-Comp kit, the rear piece (of the two-piece) subframe bolts in with the stock lower A-arm bolts and with six new bolts that must have holes drilled where the bumpstop we just cut off were located. The directions provide you with an idea of where the holes will be, but Corder used the new subframe as a template to make sure he got it dead-on. | 
5. With the rear part of the subframe bolted in place, Corder supported the differential with a screw jack and removed the three bolts that still held it in the stock location. Free of the truck, the front differential was then lowered into the cradle of the new subframe and bolted loosely in place. The CV-shafts, differential vent, and central axle disconnect can all be left in place by doing the install Corder's way. | 
6. The front half of the subframe was then bolted in place. Pro-Comp has you drill four vertical holes into the truck's frame to support the new subframe. Again, by bolting the subframe into the old lower A-arm mounts, it can be used as a template to locate where the new holes need to be. With both the front and rear subframes in place, Corder then used a prybar and a screw jack to maneuver the lower A-arms into their new mounts, which are now 6 inches closer to the ground--hence the 6-inch lift. Once in place all of the bolts are installed and the nuts are left loose. |
7. GM redesigned the idler arm on the '99-and-up Silverado/Sierra to be stronger and last longer. In order to support the drop-down steering truss that Pro-Comp uses to correct the steering geometry, two new greasable rod end links are incorporated into the front lower subframe. These two links act as additional idler arms and share the stresses exerted by big tires and off-roading on the pitman arm and factory idler arm. It helps to have small hands if you are going to make these modifications to the steering with the front differential in the truck. | 
8. We don't know who started the trend of adding these anticompression struts to the now 6-inch lower subframe but we'd like to thank them. The Pro-Comp kit uses more bolts and reinforcement brackets than any other kit we've tested to hold the new two-piece lower subframe in place. So if all the bolts stay tight, this should be a strong kit. | 
9. The front half of the lift kit is completed with an optional triple-shock kit that is available from Pro-Comp. Notice how the shock hoop bolts in where the stock upper A-arm used to pivot. Also notice that the upper A-arm has been moved down 6 inches to keep them parallel with the lower A-arm. The new rear A-arm mount is actually part of the new lower subframe, while the front mount for the upper A-arm is all new and bolts in place with four bolts. Before installing the torsion bars make sure to route the stock brake lines and ABS wires so they don't get torn as the suspension cycles and the wheels turn. |
10. With the Pro-Comp kit, driveshaft vibration problems are suppose to be a thing of the past even with NVG 246 Autotrac transfer case-equipped trucks. Corder reinstalled the factory torsion bars after he relocated the torsion bar crossmember down a few inches with these Pro-Comp mounts. The new mounts index off of rivets in the frame and should be measured, marked, and drilled accurately to ensure the crossmember will bolt back in place. | 
11. The rear lift uses a combination of add-a-leaves and blocks with new longer ES3000 shocks to get the increase in ride height. Using a screw jack, and doing one side at a time Brett flew through the rear install in about a tenth of the time it took him to do the front. | 
12. These rear traction bars are available as an option from Explorer Pro-Comp to keep axlewrap down. The bars bolt to the rear axle with a plate that sandwiches between the axletube and the lift block. You have to install the rear of the bar first, and then (with the truck on the ground) mark and drill the new holes for the front mount. |