From this view, it's obvious...
From this view, it's obvious how tight the fit is for the 30-inch slick. Notice the cutting work done to the wheel lip and molding for clearance. The '66-'67 B-Body has the smallest wheelwells of all the B-Bodies, with the exception of the '65 Coronet. This type of backyard butchery could help some A-Body gearheads fit a 28x9 tire on a 7-inch rim with the proper backspacing.
Out on the street and at the shows, the factory chrome Road Wheels and Coker Classic Redline radials maintained that '60s look. The redline radials also provide a better ride and handling over bias-ply tires. For years, we have wanted to strip test a set of front skinnies (lightweight front wheels and tires), so we scored a set of 3 1/2x15-inch Weld Draglites at the Englishtown fall swap meet. Hoosier provided us with a set of their lightweight, low rolling resistant front runners (26x4.5-15, PN 18105). Now we were fully armed, ready, and waiting for our test day at E-Town.
It was October and the track would be closing soon for the winter. [Oh, I miss those days. -Ed.]
Traction Reaction
Our goal was to show how easy it is to improve the hook at the track, through simple bolt-ons and adjustments. Our test day was a windy fall day at the famous E-Town facility. For a baseline, the well-used 28x9 Hoosier slicks mounted on the cop-car wheels were placed on the R/T. Air-shock pressure was set, the pinion snubber was adjusted, and the front sway bar was disconnected. On our first pass, the R/T made its quickest 60-foot time ever with a 1.61. Thanks to the new leaf springs, a quick stomp on the gas pedal was now possible. A backup run produced an identical 60-foot with an 11.21 e.t. Now, consistent bite was established.
Here the combatants wait for...
Here the combatants wait for their strip brawl. At the weigh-in, the 15x7 cop wheel with the 28x9 slick was the heaviest at 42 pounds. The 15x8 1/2 Weld with the 30x9 radial registered 40 pounds, while the 15x7 Centerline with the 28x9 slick was the lightest at 34 pounds. The 30x9 radials are normally worth a tenth over the same size bias-ply slick, but they would have to run against the 28s in this fight. We baseline tested the R/T with the new leaf springs and the old cop wheels and worn-down 28-inch slicks. The new springs were good for additional bite, along with consistent and reduced 60-foot e.t.'s. The Centerlines with fresh 28-inch slicks were up next, and were equal in performance of the shredded slicks with identical 1.61 60-foot times-proof that the Hoosier tires work to the last race. We suspected the old air shocks were not firm enough to help plant the lighter wheel/tire combination (less unsprung weight) to the track.
Next, the five-year-old 28x9 Hoosiers were swapped for a set of the same size meats on the lighter Centerline rims. After the swap, we were still spinning slightly (hazing) and thought the new rubber would have added grip. After four passes-two back to back and two with a half-hour cooldown-the ol' Dodge ran four 1.61 60-foots, with a pair of 11.20s and 11.21s. We definitely needed new sneakers-the tread wear indicators were hardly visible on the old slicks!
We didn't realize the added traction from the new slicks and lighter wheels reduced sprung weight. Lighter wheels make it easier for a tire to unload and lose surface contact. We were sure a quick change to the QA1 rear shocks would help plant the tires. The air shocks were tossed, and we set our initial shock setting on the QA1s knob three clicks clockwise. Right out of the hole, the scoreboard read a 1.58 60-foot. We were on a good pass and turned an 11.18 e.t. A hot-lap backup pass produced an identical 1.58 60-foot, but at a slower 11.19 e.t.
After the usual half-hour cooldown, the adjustment knobs were turned three more clicks for additional shock stiffness. It worked-we hooked up with a 1.56 60-foot and an 11.16 quarter-mile e.t. A half-hour-later a backup run showed us dead-nuts-consistent traction with another 1.56 60-foot. We wanted to try a few more clicks, but were running out of track time.
We moved to the front shocks and set them at zero to retain the worn-out, old-school feature (easy to extend, hard to compress). Unfortunately, we didn't realize any gains in e.t. The old front shocks were trick units (easy to compress and extend), but they were dangerous on the road (excessive dive, rise, and body lean). For the ride home, we set the adjustment at six clicks (compression firmness doesn't change; extension stiffens with each increase in the adjustment) and the Coronet never held the road better in its 25 years of ownership.
Up front, we were anxious to try out the new set of front skinnies. The lightweight wheel and tire combo weighed 58 pounds less than the Road Wheels with redlines. We added 8 gallons of pump gas in an attempt to keep the test weight fair. The reduced rotational weight and rolling resistance scored us a similar 60-foot time, but a much quicker 11.06 at 122.08 mph. Trap speed increased by 1.25 mph from the previous best of the day. High-speed stability improved thanks to the Hoosier front-runners and QA1 shocks.
We were determined to fit...
We were determined to fit the 30x9 radial slicks within the wheelwells. The 28x9 slicks had no clearance issues since they were mounted on 15x7-inch rims with 4-inch backspacing. The 15x8 1/2-inch rims have 4 1/2-inch backspacing. We carefully hammered to stretch the inner wheelhouse back 1/2 inch. After the "tweaking," we went for a ride to make sure there was no tire rubbing. There was enough clearance, as seen here at the front of the wheel opening. These 30.0/9.0 slicks (PN 18210) have an actual diameter of 29.5 inches and a tread width of nearly 10 inches. T indicates the circumference, also known as the rollout of the tire. C07 is the rubber compound of the tire, which is a little softer than the D05 of the 28-inch slicks.
These shock extensions on...
These shock extensions on the old air shocks are a sorry sight on a street or show car. They took away from the stock look we try to maintain with the R/T. The extension prevents the shock from possibly bottoming out, if fully extended, which could unload the tires and cause spinning.
The 15-year-old, standard-duty...
The 15-year-old, standard-duty front shocks exhibited too easy compression and extension. Wimpy shocks promote poor handling and excessive body lean around turns in the road. The QA1 R-Series (PN RC1538P) feature a fixed, firm compression, with a wide range of rebound (extension) settings to control the rate of front-end rise. Front adjustable shocks allow changing the rate of weight transfer to the rear tires to improve traction. QA1's 12-way adjustable shocks were installed and presented a nice, cool, clean look. These polished aluminum shocks extend an inch more than the air shocks-no more ugly shock extensions. Adjustable shocks allow fine-tuning to different conditions and wheel/tire weights. The dial was set at three clicks for the first pass-traction increased and e.t.'s dropped. At a total of six clicks, we gained even more hook and the 60-foot times dropped to 1.56.
We installed all four shocks...
We installed all four shocks with the adjustment dial facing the inside of the car to allow for easy-to-reach adjustments. At the strip, the front shocks were set at zero; for the ride home, six clicks provided a vast improvement in road handling. Adjustable shocks can be fine-tuned to your combination, helping the tires maintain contact to the pavement.
The 15x3 1/2-15 Weld Draglite...
The 15x3 1/2-15 Weld Draglite and 26x4.5-15 Hoosier front runner is 29 pounds lighter than the Road Wheels with the 215/75R-14 Coker Classic radial redline tires. We added 8 gallons of pump gas to make up for the weight reduction of 58 pounds. Afterward, the lighter wheel/tire combo still improved the e.t. and trap speed by a full tenth and 1.25 mph. Except for quicker e.t's and more mph from less weight and rolling resistance, front skinnies are not recommended for highway use.
In the end, the 30-inch radial...
In the end, the 30-inch radial slicks netted the best bite, e.t's, and mph, as compared to the bias-ply 28-inch slicks. Most stock eliminator racers use the Hoosier radial slicks for consistency, quickness, and winning races. Now when the R/T is headed for the track, Hoosier's radial slicks and front runners will be in the trunk!