Block kits are an extremely easy way to lift or lower your ride, and are probably the most cost-effective to boot. GMC Sierra block kits will normally come with everything you need, including the blocks, U-bolts, washers, and nuts. Keep in mind that it is never advised to stack blocks, so if you need more lift or drop than blocks alone can offer, we suggest also purchasing a set of lifted or lowered GMC Sierra leaf springs.

Block kits effectively lift or lower your vehicle by acting as spacers between your straight axle and leaf springs, using longer U-bolts and new fastening hardware to secure the blocks to your GMC Sierra chassis. Be sure to check your pinion angle after installing a GMC Sierra block kit and, if necessary, install pinion angle shims to correct any misalignment. This will keep your driveline happy and in proper working order for years to come.

Q: Does a block kit lower the front or the rear of a truck/SUV?
A: Block kits are used to lower the rear of a truck only. Due to the fact that the front and rear suspension on trucks are different (in order to accommodate the load of cargo a truck bed is built to carry), blocks kits are not applicable to front suspension of any truck. A common form of front suspension on trucks is a set of coil springs for example, and block kits do not work with coil springs.

Q: Is a block kit only used on certain vehicles?
A: Block kits are only used on vehicles that utilize leaf springs in their suspension set-up. Block kits are used in conjunction with leaf springs.

Q: What do block kits do? Why purchase a block kit?
A: Block kits are designed to lower vehicles that use leaf spring suspension (such as most trucks), and are normally offered in 1-inch increments. There are different ways to lower the rear of your truck, and in general, using a block kit is considered the most affordable and easiest way.

Q: How do you install a block kit?
A: Block kits are installed between your rear axle and the leaf springs using U-bolts to fasten the leaf spring and block together. The U-bolts are specially made for the size of blocks you get, so always rest assured that the U-bolts that come with the block kit you purchase will be the right size to fasten your new blocks. You install the block kit beneath the leaf springs if you want to lift the vehicle, and you install them above the leaf springs (which need to be re-located beneath rear axle) to lower it.

Q: Can a block kit be used to lift a vehicle?
A: Yes, absolutely. You can put the block kit on other side of the leaf springs to 'raise them' and your vehicle. You can use a block kit to raise or lower your vehicle; the block kit system works the same either way by putting space between the leaf spring and axle. You just decide if you want to make the leaf spring go up (lower the vehicle), or down (lift the vehicle).