It was time to update and...
It was time to update and tune the suspension/tire combination on the ol' R/T. An assortment of outdated and original suspension parts were no longer assisting in consistent hookups. Here we are on a run testing the effectiveness of new rear QA1 shocks and Hoosier slicks.
When we last tried to strip test our '67 R/T with its new Barton 493 wedge ("Long-Armed Wedge," June and July '03 issues), it was difficult to hook up on launch. The 60-foot times varied from 1.63 to 1.73 seconds, depending on how fast the accelerator was depressed (slowly walking it out worked best). We almost broke into the 10-second zone with a traction-limited 11.01 quarter-mile e.t. A few tenths were lost due to tire spin in the first 10-200 feet, and we finally realized it was time to update the old B-Body's suspension system. the Barton engine was out of the car for some "other workings," and we wanted to strip test a couple suspension components. We decided to install a Ray Barton-supplied 440 short-block, as well as the top end from our 493.
Springs And Things
Confident that the Coronet's chassis was solid and stiff enough due to a solid body and subframe connectors, the first step was to focus on the leaf springs. The original 426/440-type leaf springs with five leafs on each side-aided by the one half-leaf on the left side and the two half-leafs on the right-were no longer tough enough to handle the torque of the stroked wedge, so we ordered a set of custom replacement springs from Eaton Detroit Spring. These springs featured an extra leaf (now six) on each side to reduce spring wrap-up. After installation, the ride, handling, and traction (it didn't spin or go sideways as much punching it at 50 mph) was noticeably better on the backroads.
We'll gladly trade a stock,...
We'll gladly trade a stock, cushy ride for better hook at the track and firm handling. Time and money is well spent in preparing the rear suspension to exceed stock-type performance limitations. Eaton Detroit Spring custom-built us a stronger set (an extra leaf on each side for less spring wrap) of the 440/426 Hemi-type leaf springs. QA1 sent us a set of their ultra-high-quality adjustable shocks (PN TC1539P). After cleanup of all the suspension parts (except the new shocks) we used Eastwood's paint products.
Further suspension tuning consisted of a trackside install of QA1's 12-way adjustable shocks. These shocks allowed the driver to switch between a softer "street" feel, and a help-plant-you-in-the-seat "strip" feel. We'll let you know what settings worked for us.
The antiquated shock setup on our Dodge was typical of the dual-purpose car built between the 60s and the 80s. Up front, weak standard-duty shocks were used for fast front-end rise to aid weight transfer to the rear tires. These wimpy front shocks were scary on the highway, with excessive dive and rise tendencies from the dips on the road. In other words, the R/T suffered with poor road-holding ability.
Out back, air shocks supported an even stance, with 40 psi in each shock when driven on the street. For the track, 10 psi in the left shock and 20 psi in the right shock provided a good launch-that is, until they faced the torque monster. The compression (bump) and extension rates (damping force) of the outdated air shocks hurt both the e.t.'s and the handling.
With 12 adjustment settings, the QA1s offer a wide range of bump and rebound control. These adjustable wonders lower e.t.'s, aid in high-speed stability, and reduce body lean by leaps and bounds.
Once we trial fitted the 30x9R-15...
Once we trial fitted the 30x9R-15 Hoosier slicks on the 15x8 1/2-inch rims, the sidewalls rubbed the inner and outer section of the wheelhouse. A little creative modifying to stretch the wheelhouse to within 1/4 inch of the quarter-panel was all that was required. Before the stretch-job began, the wheelhouse was 1 1/2 inches from the quarter-panel. Instead of rolling the wheel lip and molding, it was cut back 1/2 inch for tire clearance.
Hook And Roll
Most of us Moparites realize that various wheel and tire weights can make a difference in street or strip performance. The sprung and unsprung weight of different wheel and tire combos (heavy to light, light to heavy) change how a suspension reacts. That's a good reason to have shocks that can be adjusted to meet the changes in suspension reaction.
Lighter wheels and tires have been providing lower e.t.'s and more mph for many years. We've been running heavy, stock wheels for too long. To perform this test of springs, shocks, wheels, and tires, we needed to gather up the appropriate parts. We had a set 15x8 1/2-inch Weld Draglites left over from a previous car, as well as a swap-meet set of 15x7-inch Centerline Auto Drags, and a couple15x7 cop-car wheels that would handle an old-versus-new 28x9 Hoosier slick test. To further combat our traction woes, Hoosier's new 30x9R-15 radial slicks (28s are not available yet) will be put to the test. These radial-design tires offer less rolling resistance, along with the advantage of a larger footprint. The radial slicks were mounted on the 15x8 1/2 Weld Draglites (the wider rim spreads the tread more evenly for better tire-contact patch).