I purchased this '70 Challenger R/T in 1994 in Minneapolis. A lady who lived in Fargo, North Dakota, purchased it new in 1970. During the summer of 1994, I rebuilt the engine and transmission. in 1996, I rebuilt the Dana 60 rear axle and installed 3.54 gears in it. It originally had the Super Trak Pac option with 4.10 gears, and I didn't like the high rpm it would turn on the highway. One day in 1995, while I was racing my buddy in his '68 barracuda, I wound up going into a ditch at about 110 mph, and the front end nosed into the far side of the ditch. This in turn spun the car four times, and bent the front bumper and frame. Luckily, the ditch was very wide and fairly shallow, and I didn't roll the car over. The wreck broke both motor mounts, smashed both headers, the front valence panel was completely smashed in, and I broke the transmission mount and completely demolished my shifter linkage so that it was stuck in fourth gear. It's a testament to the awesome power of the 440 engine that I was able to pull myself up out of that ditch in fourth gear alone, and get down the road to a gas station where I was able to call a tow truck.
By 1997, the body was in bad shape. The body was completely rusted, especially the trunk and floor pans. Many of the spot welds that hold the inner fenders to the shock towers were broken, and there was a lot of flex in the body's front end. The nicest thing about the car at that time was the interior, which, aside from the carpet and headliner, was still in pretty good shape. The car was originally painted Top Banana Yellow from the factory, and whoever painted it black did not even bother to strip the yellow paint off first, they just painted over it. As a result, you could see yellow paint showing through everywhere there was a chip in the black.
Since the restoration would now require massive sheetmetal and bodywork, I started searching for a good body shop. I met Dennis and Sean Duke of Warsaw, Missouri. They run a small business called Duke's Body Shop. All the sheetmetal that needed to be replaced was. This includes the rear quarters, inner front fenders, trunk floor, and the front and rear floor pans. When the body was completely repaired, it was covered in Plum Crazy Purple.
In the latter months of 2000, I began entertaining the idea of installing an overdrive in the Challenger. I had already rebuilt the Dana 60 and replaced the 4.10 gears with 3.54 gears, but still wasn't happy with the high-rpm highway cruising. I researched several options, and the best one available in early 2001 was a new overdrive from Gear Vendors. However, Gear Vendors would not have the new overdrive for the A-833 ready until roughly January 2002. In the meantime, I discovered (in early December 2001) Keisler's new five-speed kit for E-Body Mopars. I received the new transmission, and after I completed the install in March 2002, I started the next big project for the Challenger.
The freshly rebuilt Six Pack motor was running well and had good power, but not the kind of power that I looked for. I took the car to a chassis dyno, and it pulled 341 hp at the rear wheels, which is roughly 410 hp at the flywheel. The cam I was running had 230-degrees duration at .050-inch lift, together with 9.5 to 1 compression pistons, it made for a mushy bottom end as far as torque and throttle response goes. The cam and the ported 906 heads I was running wouldn't really start pulling hard until you got close to 3,000 rpm, and would pull like mad from there on up to 6,000 rpm. Another annoyance was the finicky cold-weather starting/warm-up behavior that comes with a performance cam and Six Pack carbs using the old-style choke setup. I had solved the high-rpm highway cruising problem by installing the five-speed, but now I needed to address all of these street-drivability issues that come with the typical high-performance carbureted engines built using '60s technology. I wanted a car that wears '60s musclecar sheetmetal, but has '90s drivetrain technology underneath. I wanted a car that idles at 700 rpm, has crisp instantaneous throttle response, can get better than 15 mpg, can start instantly with one turn of the key in any temperature, and produce well over 700 hp and 800 lb-ft of torque at less than 5,500 rpm.
How was I going to get the top-end power that I wanted? Nitrous was out because I want the power-on-demand all the time and not just at full throttle; plus I don't like the idea of always refilling the bottle. Turbocharging was out because I didn't like the idea of all that extra exhaust tubing that would have to be fabricated to drive the turbo. Nope, the answer was supercharging. To use a centrifugal supercharger, you have to blow air into the intake manifold, which would mean blowing it through the carbs. Well, I didn't want to mess with all the tubing fabrication it would take to plumb air into all three carbs of the Six Pack, so those were going to have to go. The answer, of course, was to use fuel injection. With a modern electronic fuel-injection system I would solve both the blow-through problem and the driveability problems.
The first part of the puzzle was the EFI system. I decided to go with a fully programmable system manufactured by Accel. Rance Baxter set me up with a complete Accel/DFI system, which included the ECU (engine control unit or computer), the software to program it (called CalMap), throttle body, fuel rails and injectors, specially-modified Edelbrock Performer RPM manifold, high-volume electric fuel pump, fuel pressure regulator, MAP (Manifold Absolute Pressure) sensor, wide-band oxygen sensor, manifold surface temperature sensor, throttle position sensor, coolant temperature sensor, braided steel fuel lines, AN fittings, knock sensor, and, of course, the giant octopus-like wiring harness to tie it all together.
There are several well established manufacturers of centrifugal blowers: Vortech, Paxton, ATI Procharger, and Powerdyne, just to name a few. They make all kinds of complete bolt-on kits, but none of them made a kit for a big-block Chrysler. I found the answer with SD-Concepts Engineering located in Warwick, Rhode Island. They have been custom fitting centrifugal superchargers to Mopars for many years and had a complete bolt-on kit for my big-block Chrysler engine. He set me up with a complete kit that included an ATI Procharger P1SC supercharger, and custom mounting brackets for both the supercharger head unit and the alternator.
Once we got the 440 ready to run with the EFI and supercharger, we fired the engine to break-in the cam. The engine fired right up, but we noticed that it seemed to be running extremely rich. I was monitoring the EFI system on my laptop, and it was reading way too rich. We noticed a lot of white/grey smoke coming from the passenger side tailpipe, and you could tell it was fuel. Suddenly a small fire broke out under the hood on the passenger side. The passenger header got so hot it lit fire to one of the spark plug wires. We shut off the engine and put out the fire. After we got it fixed, I decided to take the car to Burlington, Iowa, to visit my Dad. The car ran fine. I always had the laptop hooked up and running while I drove. While I was in Burlington, I went out to run some errands, and while I was out I decided to do some power tuning for the first time. The very second I put my foot down the engine came apart. There was a huge crack in the driver side of the block, and a big chunk of the block had been blown out. I pulled a valve cover and could see four lifters and pushrods on the driver side. After pulling the intake manifold, I found that an entire section of the camshaft was missing. The pushrods and lifters on the passenger side were also in the crankcase. So with my 440 in ruins, I had to come up with a plan for a replacement bullet. Thankfully, nothing in the top end of the engine got hurt, and my investment in the aluminum heads, the EFI system, the supercharger, and the new exhaust system were ok. I called up the guys at Muscle Motors in Lansing, Michigan, and ordered one of their 493-stroker short-blocks. I was going to try to have the car back on the road in time to make the Mopar Nationals on August 2. The new short-block was ready on July 26, and I drove up to Michigan to get the new engine.
With the engine back in, we went back to the dyno. While we were dyno tuning the engine, we discovered that my fuel system was not up to the task of supplying this engine under full boost. Unfortunately, we didn't find this out until we had done a couple of pulls up to 5,000 rpm, and apparently that was all it took to do damage. The injectors went static (100-percent duty cycle), and the engine leaned out. Too much heat built up and burned off the oil film protecting the sides of the pistons and resulted in heat damage to the number one and number eight pistons. We also had detonation, which smoked the number one spark plug.
So to make a long story short, my fuel lines were just barely big enough to support 600 hp. With the supercharger, I needed at least a half-inch or AN-8 fuel line. what happened on the dyno is my fuel lines simply could not flow enough volume when we went full power under boost, and this is why the injectors went static, and we leaned out. Of course, now besides rebuilding the engine again, I was going to have to fix the undersized fuel system. I decided to go with a really big main fuel line. I would increase my main line size from 3/8- to 5/8-inch. I decided to bore the block .030-inch over, which will increase displacement from 493 to 500 ci. For this new engine buildup, I went with a hydraulic roller cam. The new cam has a bit more duration and 12 degrees of overlap. The increased overlap will bleed off a little cylinder pressure at low speeds, so to compensate I ordered new Ross racing pistons with a smaller 24cc dish to increase static compression ratio from 8.6 to 9.2. This time I had the pistons ceramic coated to give a little more protection against the increased combustion temperatures this supercharged engine can generate.
I sure am getting tired of rebuilding engines for this car, but here we go again. The car goes to a shop called Automekanika located in Spring Grove, Illinois, and is run by Ed Kowbel. The dyno, SpeedLab, is also located in this shop. Because the car was already there for dyno tuning when the engine got hurt, I decided to just have the engine rebuilt there.
After getting the engine all reassembled and running again, I discovered the oil was getting contaminated with coolant. That usually means a blown head gasket. So tear the top of the engine down... again. After tearing the top of the engine down a couple different times, I had the cylinder heads pressure tested. Found out there was a small crack in the number one cylinder's exhaust port that would open up when the head heated up and then would let coolant leak through from the water passage. So I had to have the head welded to fix that. that was the last problem.
With another trip to the dyno, we achieved 783 hp at 5,123 rpm, and 849 lb-ft of torque at 4,424 rpm.