Project Six Pack - All For One And One For All
Caltracs Monoleafs And A High-Altitude Converter For Project Six-Pack
From the April, 2002 issue of Mopar Muscle
By Ross Clark
Photography by Ross Clark
Here is Project Six Pack as...
Here is Project Six Pack as it looks today. Our plan was to get the big B-Body to hook and haul on Denver's mile-high Bandimere Speedway in Colorado. Our latest changes resulted in wheels-up action like this.
Editor's Note: Project Six Pack was one of the most famous cars of the '70s, covered in-depth during the early part of that decade in the now-defunct Super Stock & Drag Illustrated magazine on the Stock Eliminator trail. Now 30 years in the making, we are happy to bring you this update as the car returns to bracket competition in the Colorado Rockies. Former readers of HPM have followed some of the other changes made to the car in the last few years.
Most magazine project cars, despite good intentions, tend to be rather short-lived. The '69 M-code Road Runner seen here is the exception. This project first appeared in Super Stock and Drag Illustrated Magazine in the February '70 issue for a lace-painting feature, and officially became Project Six Pack in April 1972. Back in the early to mid-'70s, owner and SS&DI field editor Ted Struse, along with partners Mike Smith and Terry Welsh, campaigned the car in Stock Eliminator, setting six NHRA national records in the process. Now restored and sporting a 15:1 McCandless Performance low-deck 451-inch stroker and some nine-second time slips, the car would be perfect for nostalgia racing. Trouble is, there is absolutely nothing in the Denver area but brackets.
In his mid-'50s and forced to contend with Parkinson's disease, Ted had to rule out traveling to other parts of the country to compete in nostalgia meets, and he even considered putting the car back into street trim. Because of the car's racing heritage and the fact it runs so well in its current configuration, all agreed it would be a shame to take it apart and start over without further exploring its potential.
This shows the "old" way of...
This shows the "old" way of setting up a Mopar with Super Stock springs. The theory was to induce rise and separation in the suspension, thus planting the tire. Notice the springs are fully extended, the slick is fully out of the rear wheel well, and the whole posture looks awkward. In the early days of Project Six Pack, when we were running polyglas street tires, that lift was necessary to get any bite at all.
In that light, a phone call was made to transmission guru Frank Lupo, owner of Dynamic Converters in Delaware, to ascertain if the converter stall speed could be optimized to better-utilize the higher rpm power band of the Indy-McCandless 451 Wedge. While the car had the power, it didn't seem to come off the line like it should.
This is a prime example of why high-altitude racing is a challenge. The converter Frank originally built was rated at 6,000 rpm, and at sea level, that's pretty much what you'd get. But at Bandimere's often 8,000-foot plus effective elevation, a 4,800-rpm flash speed is about the limit for this unit. Nonetheless, the car left the line cleanly, with no trace of bog or stumble, and at an uncorrected 10.76 e.t. (which equates to a 9.98 at sea level), lack of power was certainly not the problem. We've seen legal NHRA stockers at Bandimere that run over a second slower yet can pull the wheels off the ground. Some of this may be due to the shifting of weight allowed by NHRA rules, something that has not been done to this car, but the bottom line is that the car was just not in the power band off the line.
As luck would have it, East Coast Max Wedge campaigner Joe Aluise, the first NHRA Stock Eliminator record-holder in the nines, made a visit to Denver to do some high-altitude running a while back, and collected quite a bit of data while he was here. Since we knew the Aluise crew also used Dynamic converters, we asked if they would be willing to help us out with some concrete figures on how converter performance varied from sea level to Bandimere. They knew of Project Six Pack and were more than happy to help.
The new unit that resulted from this meeting of the minds has a nominal stall-speed rating of 6,700 rpm. The general rule of thumb is that stall speed should be approximately 1,500 rpm less than your shift point. Running at sea level, this would be too much for our combination, which is shifted at 7,200-7,500 rpm. But at Bandimere's elevation, Joe Aluise's data showed that we could expect to lose approximately 1,000 to 1,200 rpm in stall speed. While that seems like a lot, our initial testing showed an even higher 1,400 to 1,500 actual rpm loss! In other words, our 6700-rpm converter became a "5,200" at our mile-high elevation.
Moveable-link suspension systems,...
Moveable-link suspension systems, like four-links and ladder bars, may offer the ultimate in adjustability, but there are certain drawbacks. One is expense. Another is that they are not allowed in some classes, such as NHRA Stock Eliminator. The legal CalTracs system accomplishes the goals of adjustability and adds what John Calvert refers to as "correction of the pushing point vector," but at a much lower cost. Basically, a car with a traction system that uses the "original" vector as illustrated will rise so dramatically on launch that it will unload the tires, causing wheel spin. The car then comes down, gets a good bite on the track again, rises excessively, and spins the tires again. Obviously, this is hard on elapsed times as well as parts.
We installed the new converter,...
We installed the new converter, but left the old suspension still in place, and home video showed clearly what was happening. While the quality of the photo from the tape is marginal, you can see that the torque of the engine is overpowering the springs, and trying to tuck the right rear slick under as it rolls the body to the right. On the run, the car pulled to the right quite severely. Although there didn't appear to be overt tire spin, the car was reacting as if the track were slippery.
John Calvert's CalTracs bars...
John Calvert's CalTracs bars are refined traction bars, similar in construction to the traditional slapper bars, but with a more sophisticated approach. He has recently released a unique monoleaf rear spring setup specially engineered to work with the CalTracs bars. The new springs offer a substantial weight savings over the conventional spring pack.
CalTracs, like four-link and...
CalTracs, like four-link and ladder bar systems, flatten out the pushing vector and smooth out the motion of the rear suspension. They were originally devoloped for NHRA stock eliminator, which dictates that no portion of the add-on traction device can be forward of the front spring eye. In order to keep the geometry proper, John Calvert devised a pivoting setup that meets the letter of the rules while still holding true to the optimized push point.
Frank Lupo, of Dynamic Converters,...
Frank Lupo, of Dynamic Converters, has been involved with Project Six Pack since he was a kid. His latest revision of the torque converter added an extra 400 to 500 rpm to the "flash." (This is the maximum rpm that the converter reaches when hammered to the floor at about 10 miles per hour in high gear). At high altitude, it's not uncommon for a converter to lose 1,000 to 1,500 rpm from its sea-level performance. We may add more rpm next season, but even this change made a big difference off the line.
Our suspension guru, NHRA...
Our suspension guru, NHRA national record holder Gary Gokey, has years of drag racing under his belt. Sometimes you get too close to your own situation, and a fresh perspective makes it a lot easier to understand what's going on. A keen observer, Gary doesn't miss a trick.