Top Fuel: An Essay

By Ken Sitko

Drag racers tend to have their own idea of the “Golden Age” of drag racing. The truth is, each time period has its own appeal for different reasons. When drag racing first began 60 years ago, times were simple, costs were low, and racers came up with their own versions of a drag car with their own innovations. In the early years, safety took a back seat to making the cars faster by any means possible. Pushing the performance envelope started since day one and has never stopped. How this could be achieved, despite the many challenges encountered along the way, continues to evolve to this day.  Here is a look at how it transpired.

In the mid 60’s, the clunky designs of early drag machines morphed into the more traditional front engine dragsters.  Racers really started taking pride in the looks of their dragsters, rather than just throwing together something light and fast. The success of cars like the Greer/Black/Prudhomme dragster spawned many similar designs, and these streamlined machines became the weapon of choice to assault the quarter mile. They were powered by early and late model hemis, Chevs, and any other combination that would make horsepower. The blowers, back then, started their lives on big trucks.  They definitely increased horsepower but didn’t make enough air to blow things up really bad. Still, there was the odd explosion, especially when nitromethane was introduced.

Some racers branched off into funny cars years later, as they had the same powerplant, but the chassis had a production style body on it. The funny cars quickly became a fan favorite but were a bit slower because of the extra weight. Performance was limited by the technology of the time, and engines had a relatively long life. The cars were pulled to the track on an open trailer or a ramp truck.  Room for spare parts was not needed, as there weren’t many breakdowns. Most racers were weekend warriors anyway on a fixed budget, so their machines had to be reliable to keep costs down.

Slowly, the cars evolved into more serious machines. A few guys started building aftermarket superchargers which were a pretty good upgrade from the GM blower. At the same time, fuel pumps from Hilborn and Enderle helped to deliver enough fuel to match the blower boost, and ignition distributors were abandoned in favor of Cirello, Mallory and Vertex magnetos that put out almost 3 amps! The big picture here is that these components were very complimentary with each other. If the drag racer didn’t get too greedy and push their equipment too hard, the 3 amps mag would work in near perfect harmony. Well, that wasn’t going to last long, was it?

Back in the late 60’s and early 70’s, top fuel engines were mostly comprised of stock “off the shelf” components. These were made up of cast iron blocks and heads, stock stroke crankshafts, flat tappet camshafts and blowers whose boost numbers could compare to that of a hair dryer. I was 12 years old when I learned how to assemble cylinder heads and loved putting a bright polish on the combustion chambers and the exhaust ports with a die grinder and flapper wheel. The valve springs were set up at 200 lbs with the valve closed, which today wouldn’t last a fraction of a second after hitting the throttle. The cast iron heads didn’t last long either, you had to have a few spare sets in case the seats cracked or the chamber broke. Water was poured into the heads and block before the warmup and left in for the run. It was usually dumped out of the engine by the driver as soon as he or she climbed out of the car, then filled back up when the car got back to the pits. With the 6-71 on top, there was little maintenance. But, nitro is unpredictable and racers are greedy for performance. Carnage was inevitable. One thing about cast iron; once it had a hole or a crack in it, it was almost impossible to repair. By the time aluminum blocks and heads came out, the scrap iron pile was getting pretty high.

The cast iron block was past its limit as horsepower levels were already too high for this brittle material. The advent of the aluminum block lightened the engine assembly by 100 pounds and added the flexibility needed to withstand the ever-increasing torque and stress. The Keith Black aluminum block was released in 1974 and was a huge improvement to the longevity and serviceability of the nitro engines. It featured removable iron sleeves that could be swapped out if damaged by a burned piston, so blocks suffered no permanent damage due to regular wear and tear. It could also handle the horsepower of the day, and for years to come as the aluminum was able the absorb the shock of detonation without cracking. Many 6-second funny cars and dragsters still use the surviving original blocks that are now over 40 years old.

Factory aluminum heads were used when nothing else was available. They were just as prone to cracking between the seat and the spark plug hole as the cast iron versions were. Eventually, Dart came out with cast aluminum cylinder heads that were much superior to the Dodge versions. The material was tougher, and the seats would stay in place without cracking. These were used for 5 or 6 years until something better arose. It was not until some enterprising racers started making heads out of solid (billet) aluminum that the situation stabilized. Solid heads meant no water in the engine, so solid aluminum blocks (no water jackets) were the next step in the evolution. Water had been used as a coolant and to keep the temperature even between the cylinders, but it was a pain in the butt. The solid aluminum blocks turned out to work just as well as a temperature sink and were much stronger. Down the road, this would turn into billet blocks, which became absolutely necessary to withstand the horsepower levels of today.

The first successful rear engine dragster was debuted in 1971 by Don Garlits after surviving a horrendous clutch/transmission explosion that cut half of his foot off in his front engine car. Because of his tremendous success, by 1972 rear engine top fuel dragsters were being built professionally using Garlits’ car as the template. The chassis builders were all trying to rise to the bar Big Daddy had set.  Going fast was still the primary goal, but the bodies were now hand formed works of art, and no effort was spared to paint them beautifully as well. The only available blower was an aftermarket 6-71, built by either Mert Littlefield, Ed Pink, Don Hampton, and a host of others. The points magneto was still enough, as was a fuel pump that flowed 13 gallons per minute (gpm). Fuel system advances coupled with spark and boost would start the transition from 1500 horsepower engines of the time to the 11,000 horsepower monsters of today.

Most top fuel cars of this era used commercially available stock stroke crankshafts. Inventive racers such as Beck and Peets had the facilities to make their own strokers, which gave the engine a much bigger swept volume and increased the cubic inches. More cubic inches equal more power, and anyone equipped with strokers had a distinct advantage. From ’71 to ’74, Beck used 1/4, 1/2, then 3/4 strokers to jump ahead of most other competitors until other racers were able to get a hold of their own.  When the engine sizes started getting carried away, NHRA put a 500 cubic inch limit on the fuel classes which made the crank of choice a 3/4 stroke (4.500 inches). This made the engine 496 cubic inches with a 4.187 diameter piston. While they made a bunch of power, the homemade cranks didn’t have the strength needed to withstand the sustained pounding of nitromethane fuel. Keith Black came out with the first billet crankshaft, and racers were chomping at the bit to buy one to level the playing field. Soon after came Velasco, Bryant, and Crower to keep up with racer’s crankshaft needs.

As mentioned earlier, the fuel system needed to undergo a complete transformation to attain today’s horsepower levels. The progression was slow, however, as the additional gallons per minute required sufficient spark and boost to keep it lit. No one aspect could be advanced too far without causing an imbalance in the engine combination. Each combination of air, fuel or ignition had to progress in small steps, as there was no method at the time to calculate how to make everything optimal all at the same time. The first hints of progression came the moment that the Snake ran 5.63 in Indy, bettering the field by 2/10ths of a second. This was relatively unknown until years later. During an interview with broadcaster Steve Evans, Prudhomme admitted that innovations with the fuel system had fueled his dominance over the field for many years. Once others started to catch up, they found more ignition was needed as well, so the easy answer (and the only one available) was to add another magneto and run 2 spark plugs per cylinder. Racers Armstrong and Bernstein even tried 3 magneto’s and 3 spark plugs, until NHRA limited the class to 2.

The superchargers had to get better as well. I remember the first 8-71 that we got from Mark Danekas; we traveled to the old Mission Raceway Park and proceeded to burn all 8 pistons on every pass. We didn’t have enough fuel and needed a bigger pump. This see-sawing interaction between pump, ignition, and blower continued for 20 years until necessary limitations forced the slowing down and refinement of the technologies. During the transition period, blowers kept growing in length, from 8-71, to 10-71, to 11-71 for a short time, then to 12, and finally to 14. Mags went from 3 amp to 5, then 7, and 9, until MSD decided to obsolete the archaic points system with the invention of the electronic magneto. Suddenly we had 12 amps, 20, then the penultimate 44-amp mag. At the same time, pump manufacturers were creating 16 through 24 gallons per minute flow, then dual 24’s. When I interviewed Gary Beck 6 months ago, he said that his historic 5.39 run in 1983 Fremont was a direct result of installing a high-volume Waterman pump. It was the most fuel he had ever pumped into the engine. Top fuel cars now run monster pumps that flow 100 gallons per minute, and it is the balance between fuel, air, and ignition that kept the engines running fast in each era. Fast, or blown up. This summed up the way things were in the 20 years of transition.

Often seen spectacles of the 1980’s; John Force diving out of his escape hatch while the car was still rolling and on fire. Another was Mike Dunn breaking a crankshaft in the lights, exploding the supercharger, buckling the body, and stripping a complete car to a bare frame by the time it slammed into the net. Numerous top fuel dragsters launching blowers a hundred feet in the air (before blower bags) taking wings and tires with them, making for a harrowing white-knuckle attempt to stop their machine from 250, 300 or more miles per hour. Sadly, these were common occurrences during the 1980’s while crew chiefs struggled to find the right combination and dreamt of parts that hadn’t yet been built.

The meshing of the three crucial elements of top fuel racing, air, fuel, and ignition had still not reached maturity in the 70’s. One man, Dale Armstrong, became a pioneer in the modern world by helping to develop an on-board computer.  He hooked it up to Kenny Bernstein’s race car; once data started pouring in, it opened a whole new world to the potentials of the top fuel engine. Instead of guessing at what the car wanted, he could see the performance of every component during the run, see the result of changes made between runs, and judge for himself any potential effects they might have.

Said by Dale Armstrong: “People ask me what was the single thing that made the biggest progression in drag racing from the 1970’s when no gains were being made, and I tell them it was the computer. It changed the sport in a way nothing else did. There’s nothing else that even comes close. Front-engine dragster to rear-engine dragster, nothing has compared to what the computer did. That was one step, and it was over. The computer went on and on, and to this day it’s still doing it.”

Data from the on-board computer has made nitro engines what they are today. Tuning changes and innovations in equipment are now calculated instead of made by trial and error, thus the tuning of one of these engines, done by a crew chief that knows what he is looking at, is becoming an exact science. Errors in the form of engine carnage are typically the result of overused or faulty parts, not a result of a miscalculation. The blower, ignition, and fuel are as close to balanced as it has ever been, and probably will ever be. Top fuel dragsters now travel 1000 feet in an incredible 3.6 seconds at 330 miles per hour. These machines use dual 44-amp magnetos, enough power to weld with. Superchargers make 50 psi (pounds per square inch) boost and fuel pumps flow in excess of 100 gallons per minute. Crew chiefs are always looking for more though, so small increments in performance will still be achieved. What is happening now is that the fields are getting tighter. One or two-hundredths of a second separate the top teams, so driver reaction time and the ability of the crew chief to interpret the data, read the track, and prevent mechanical failures is of prime importance.  New innovations and striving to improve will make drag racing more competitive and exciting than ever before.


About the author:

Ken Sitko began wrenching on his father’s nitro dragster in 1971. He was exposed to a great number of top fuel cars and personalities from the age of 10, making road trips to Sanair, Seattle, Spokane, Pomona, and Salt Lake City. Ken’s home track was the state-of-the-art Edmonton International Speedway where an amazing 6 Local top fuel dragsters regularly took on the best of the Northwest. When the Speedway closed down in 1983, Ken left the nitro classes behind racing his own top alcohol cars until 2010. Since 2011 he has built and continues to campaign a nitro funny car with his father George and his sons Troy and Nathan.