Last month we introduced our '71 Chevy Suburban and equipped it with some stout axles and lockers, along with a set of 4.88 gears. For this issue's installment of Project SuperBurb, we decided it was time to revamp the Sub's tired old suspension. Dreams of lots of lift and tires big enough to run over import cars filled our heads--but then we remembered that our Burb had to serve double-duty. Actually, it has to do more than double-duty, as the idea is to build one vehicle that could serve as an awesome tow rig, a comfortable daily driver and a capable trail rig.
For those reasons we decided to dial back the lift and tire size, since towing with 40-inch mudders didn't sound like a good idea. Plus we wanted a tire size that was somewhat easy to replace. Huge tires aren't easy to find in remote areas, which is where we tend to need them.
With all that in mind, we decided on a conservative 6-inch lift and 35-inch tires. For the 6-inch suspension system we turned to Superlift. Until very recently, all that was available from Superlift for the '67-'72 Chevy crowd was the company's heavy-duty front springs. But we felt that those would be a bit stiff for our purposes.
We were in luck, as the folks at Superlift informed us that the company's softer Superide springs were going to be available for the '67-'72 Chevys. Even better, we could get the first set. So after our new suspension arrived we busted out the tools, cleared out the driveway and went about slapping the lift on the Sub. What follows are the details and results of our toil.
So what's in store for the next installment? How does 340 hp, 450 lb-ft of torque and an overdrive sound?
BEFOREThe Before and After
We were surprised at the amount of flex that the Suburban had in stock condition. Most of it was due to the stock springs, which were completely worn out. Because of the softness of the springs, the Suburban was all over the road, and on the trail it would quickly blow through its meager suspension travel. In stock form our Suburban managed a 562 RTI score on a steep 30-degree ramp.
AFTERAfter the lift was installed, we hit the 30-degree ramp again. Though contact between the front tires and the fenders stopped our progress before the Burb could achieve full flex, it did manage an RTI of 603. We expect a slightly higher number after some fender trimming and after the springs break in.
Just getting the Burb up on the 30-degree ramp in stock condition was an ordeal, as its bumper would barely clear. After the lift was installed, this was not an issue. | 
As the Burb reached full flex in stock form, the rear bumper was almost on the ground. This too would not be a problem after the lift was installed. | 
Our efforts to get an RTI score after the lift kit was installed were hampered by the front tires rubbing. With a little fender trimming, we should be able to achieve full flex. |
Important Numbers
Installing a suspension system isn't just about flex. We made large gains in approach and departure angles that will help the big Burb on the trail. The most impressive gain was clearance under the low-hanging transfer-case crossmember, and improvement that will help keep the Burb from high-centering. Check out the following before and after numbers.
| | Before | After |
| Approach Angle (Degrees) | 33 | 52 |
| Departure Angle (Degrees) | 21 | 32 |
| T-Case Crossmember Clearance (inches) | 10 | 19 1/8 |
| Front Differential Clearance (inches) | 8 3/4 | 10 1/4 |
| Rear Differential Clearance (inches) | 6 3/4 | 8 3/8 |
More Axle Beef
After last month's axle install we decided to do a little light wheeling. We quickly found that one of our hubs was busted. Upon disassembling the front Dana 44 we were horrified to discover puny axleshafts that looked like toothpicks, and tiny U-joints that looked like they came out of a Jeep. A quick call to Warn solved our problems. First we ordered a set of Warn's premium manual-locking hubs for our Dana 44. But we knew we had to get rid of those puny axleshafts, so we also opted to get a set of Warn's 4340 chrome/nickel alloy shafts. They don't neck down like our stock ones did, and we can use the bigger and stronger 297X U-joint. Another nice feature is that they are machined to accept full-circle retaining clips, which do a much better job of retaining the U-joint.