2007 GMC Sierra Buildup - Belltech 641SP Lowering Kit

For this month's Fantastic Four we've got a crew cab GMT900, the most popular cab configuration of the most popular fullsize truck on the market right now. If you've got a new Chevy or GMC, pay attention, because we did the hard work of finding parts that work together to make a great-looking, functional cruiser. On the performance front, we improved mileage, power, and sound thanks to K&N Filters and Heartthrob Exhaust. The tandem gave us a 22-RWHP boost in power and improved the Sierra's throttle response. We decided to trust the handling of a tuned Belltech suspension that will allow for a customizable ride height. Using an adjustable mounting point at the shackle and spacers in the sport-tuned coilover shock in the front, we can dial-in the suspension in exactly how we like it. Combined with the 2-inch drop spindle we'll have a range of 1-4 inches of drop. and unlike many lowering kits where the ride suffers, this kit was specifically engineered to provide improved handling and comfort. We haven't forgotten that we want this truck to look its best, so Elite wheels, General Tires, and T-Rex grilles were all called upon to make sure this truck ups the ante on all fronts with color-matched style. Check out how our neighborhood 4 Wheel Parts install tech, Jason Green, transformed the ride and handling of this Sierra before we upped the looks and performance at our very own Tech Center.

We rolled the Sierra into 4Wheel Parts completely stock.
Belltech's kit came with spindles and adjustable height coilovers for the front and hangers, shackles, shocks, and flip kit for the rear. Everything we needed for improved handling, a smooth ride, and looks that'll turn heads. This kit isn't your typical drop kit, it was designed with a no compromise attitude, and we couldn't wait to get it bolted on.
Belltech's kit came with spindles and adjustable height coilovers for the front and hanger
Jason began the front end disassembly by popping the hood to access the three bolts on each coilover from the engine bay. Then he lifted the truck, removed the wheels, and removed the coilover.
Jason began the front end disassembly by popping the hood to access the three bolts on eac

The two caliper bolts were removed, the wheel speed sensor was unclipped, and the caliper was hung from the frame to eliminate tension from the brake lines. Next, Jason unbolted the hub from the spindle. Here you can see the steering has also been removed and the sway bar end link is loosened, ready for removal.
The two caliper bolts were removed, the wheel speed sensor was unclipped, and the caliper
With the factory coilover mounted in a spring compressor, Jason removed the nut securing the shock to the mounting plate. Here's the side-by-side comparison. Note that the Belltech adjustable shock is nearly the same size.
With the factory coilover mounted in a spring compressor, Jason removed the nut securing t
For our application, the lowering will be all in the spindle, but if we had wanted to go lower or higher we could have tailored the number of these spacer rings to dial in the ride height.
For our application, the lowering will be all in the spindle, but if we had wanted to go l

Back to the spring compressor, the new shock met the factory bracket and spindle as well as the factory internal bumpstop. Jason also transferred over the threaded tabs from the factory shock.
Back to the spring compressor, the new shock met the factory bracket and spindle as well a
The factory hub was bolted to the Belltech spindle. This can be done with the spindle mounted, but the uppermost bolt needs to be inserted before the upper ball joint now that the hub is located closer to the top of the spindle.
The factory hub was bolted to the Belltech spindle. This can be done with the spindle moun
Jason bolted in the spindle, replaced the brake rotor, and finally the caliper on his way to buttoning up the front suspension.
Jason bolted in the spindle, replaced the brake rotor, and finally the caliper on his way

For the rear, Jason first dropped the factory trailer hitch to make room to loosen the leaf spring.
For the rear, Jason first dropped the factory trailer hitch to make room to loosen the lea
After removing the U-bolts, a C-clamp was used to hold the spring pack while the leaf spring center bolt was removed and reinstalled upside-down. This is necessary to index with the flip kit hardware.
After removing the U-bolts, a C-clamp was used to hold the spring pack while the leaf spri
The spring was then removed to access the bumpstop bracket and spring hanger.

A cutoff wheel cut the weld and an air chisel pried the bumpstop bracket off before a flap disc sanded the weld smooth. A few coats of spray-on undercoating protected the bare metal.
A cutoff wheel cut the weld and an air chisel pried the bumpstop bracket off before a flap
The factory bumpstop was secured to the recently sprayed frame.
The rear shackle hanger got the same air chisel treatment to remove the three factory rivets before the Belltech hanger was bolted on. Since we were going for only a 4-inch drop, the flipped hanger and longer shackle will actually lift the rear of the truck, otherwise we'd have had 6 inches of drop.
The rear shackle hanger got the same air chisel treatment to remove the three factory rive

A bracket on the axle housing was carefully cut out to avoid damaging the rear brake line before the flip kit hardware was sandwiched between the axle and spring.
A bracket on the axle housing was carefully cut out to avoid damaging the rear brake line
With the Belltech brackets in place, the factory U-bolts were reinstalled before Jason mounted the impressive Belltech Street Performance shocks. At this point we were anxious to get the truck on the road, but there were a few more steps to go.
With the Belltech brackets in place, the factory U-bolts were reinstalled before Jason mou
Jason installed a small spacer at the transmission mount to correct driveline angles. We were ready for the wheels and tires... Sorry, you'll have to wait.
Jason installed a small spacer at the transmission mount to correct driveline angles. We w

Moving to our Source Interlink Media Tech Center, Jason Scudellari and Dan Ward popped the hood to reveal a stock 4.8L V-8. The factory intake, with its convoluted airway and baffles, was holding back some power potential.
Moving to our Source Interlink Media Tech Center, Jason Scudellari and Dan Ward popped the
Our solution was K&N's AirCharger. With the potential to unleash over 15 hp from a 5.3L, it should have our 4.8L breathing free.
Our solution was K&N's AirCharger. With the potential to unleash over 15 hp from a 5.3L, i
Step one was removing the negative battery terminal. Then the guys got to work removing the engine cover and factory intake tube after loosening the hose clamps holding it to the throttle body.
Step one was removing the negative battery terminal. Then the guys got to work removing th

The factory airbox simply pulled up from rubber ball and socket joints on the inner fender.
The factory airbox simply pulled up from rubber ball and socket joints on the inner fender
Using the supplied hardware, the K&N heat shield was installed to the inner fender.
Using a silicone coupler, the MAF sensor was mounted to the intake tube, which was loosely coupled to the throttle body.
Using a silicone coupler, the MAF sensor was mounted to the intake tube, which was loosely

The conical air filter was mounted to the MAF sensor using the supplied velocity-stack-like adapter.
The conical air filter was mounted to the MAF sensor using the supplied velocity-stack-lik
Dan placed the heat shield lid in place, fastened it down, and tightened up all of the hose clamps to finish the install. The engine bay looks ready for business.
Dan placed the heat shield lid in place, fastened it down, and tightened up all of the hos
With the truck on a lift, Dan got to work on the exhaust. This small but mighty impact gun removed the two bolts securing the exhaust behind the catalytic converter.
With the truck on a lift, Dan got to work on the exhaust. This small but mighty impact gun

The one-piece exhaust was made into a two-piece exhaust thanks to a reciprocating saw. It was much easier to remove this way.
The one-piece exhaust was made into a two-piece exhaust thanks to a reciprocating saw. It
Side by side with the factory exhaust, it's plain to see that the smaller, lighter, more efficient Heartthrob Exhaust system closely matched the factory routing.
Side by side with the factory exhaust, it's plain to see that the smaller, lighter, more e
The Heartthrob system bolted easily together and included some burly hangers.

We haven't yet decided which Hearththrob exhaust tip we'll be choosing, but you can see where it will exit. Heartthrob also makes a dual exhaust kit for '07+ GM trucks. On the dyno, the K&N and Heartthrob exhaust added 22 rwhp to the Sierra.
We haven't yet decided which Hearththrob exhaust tip we'll be choosing, but you can see wh
Our final addition to the GMC is a new T-Rex mesh grille. The core support trim was removed before we could access the bolts and clips that held the grille in place.
Our final addition to the GMC is a new T-Rex mesh grille. The core support trim was remove
To safely remove the grille without damaging the paint, the upper bumper valance was also removed. This allowed for the grille to be maneuvered so that the lower clips would come loose.
To safely remove the grille without damaging the paint, the upper bumper valance was also

Jason used an airsaw to cut the center out of his factory grille. Note that he masked the chromed plastic with tape to prevent nicks and scratches.
Jason used an airsaw to cut the center out of his factory grille. Note that he masked the
Four 1/8-inch holes were drilled in the perimeter to stealthily mount the black mesh grille with the enclosed 90-degree brackets.
Four 1/8-inch holes were drilled in the perimeter to stealthily mount the black mesh grill
For the bumper grille, Jason removed the factory tow hooks and drilled six 1/8-inch holes through the plastic valance. Small nylock nuts hold the lower grille in place with no exposed fasteners.
For the bumper grille, Jason removed the factory tow hooks and drilled six 1/8-inch holes

The black mesh works perfectly with the dark silver truck and black, machined wheels.
Back to the wheels like we promised, 4Wheel Parts mounted and balanced them and also swapped over the TPMS sensors. The Elite wheels and General tires took between 1/2 and 11/2 ounces to balance. In case you haven't balanced many wheels, that's very good.
Back to the wheels like we promised, 4Wheel Parts mounted and balanced them and also swapp
The General Grabbers offer an aggressive, directional tread for street use and have deep treads that should last quite a while. The Elite wheels were just what the owner was looking for to complement the stealthy look of the truck. The powdercoated finish should make keeping them clean a breeze.
The General Grabbers offer an aggressive, directional tread for street use and have deep t

2007 GMC Sierra Buildup Right Front Angle

FROM THE DRIVER SEAT
Once the GMC Sierra was aligned to correct the toe-out the spindles added, it drove perfectly. The owner is thrilled with the look of the Elite wheels and General tires, and the offset is dead-on. Ride quality is top-notch as well, with decent sidewalls to absorb SoCal potholes. The sound of the 4.8L was also much improved, we'll get mileage numbers as soon as the owner gets a tankfull through the truck.

YOUR QUESTIONS ANSWERED

Time Spent Working: Approximately 8 hours
Degree of Difficulty: Moderate
(Removing spring hangers is a pain but not impossibly for DIY installs, but the coilover assembly needs specialized tools)

Parts Used:
Belltech 641SP lowering Kit $1,022.00
Elite Phase 6 machined black 22x9.5-inch wheels $285.75 (each)
General Grabber UHP 305/40R22 tires $189.95 (each)
Heartthrob 2005805 single exit exhaust $358.95
K&N AirCharger 63-3070 intake kit $356.79
T-Rex Upper Class mesh main grille 51205 $375.95
T-Rex Upper Class mesh bumper grille 52205 $235.95

Total: $4,252.44
(Prices from 4wheelparts.com and autoanything.com, does not including tax or labor)

SOURCE
T-Rex Grilles 2365 Rail Road Corona CA 92880 800-287-5900 www.trexbillet.com	Belltech Sport Trucks 1075 North Avenue Sanger CA 93657 800-445-3767 www.belltech-sport-trucks.com
K&N Engineering 1455 Citrus Street Riverside CA 92507 800-858-3333 www.knfilters.com	4Wheel Parts Performance Center 809 S. Grand Avenue Santa Ana CA 92705 714-542-9800 www.4wheelparts.com
MHT Luxury Wheels 12300 Industry Street Garden Grove CA 92841 800-493-7891 www.mhtwheels.com	Heartthrob Exhaust Accessories 60819 U.S. Hwy. 12 West Litchfield MN 55355 320-693-0222 www.heartthrobexhaust.com
General Tire 1800 Continental Drive Charlotte NC 28288 800-847-3349 www.generaltire.com