|
|
Big-Block Chevy - The Pile Driver - Part 2We Install Our 509-Inch Big-Block Chevy Into A '71 Chevelle And Run It At The Track. From the December, 2009 issue of Popular Hot Rodding By Johnny Hunkins Photography by Johnny Hunkins
|
|
Last month, we built a 509ci solid-roller big-block Chevy, using the leftover block, crank, and oil pan from the 502 Ramjet crate motor out of Project X. We christened it the Pile Driver, because it pounded out 717 hp at 6,300 rpm and 651 lb-ft of torque at 5,100 rpm-all while sipping a diet of 91-octane pump gas. Those numbers are impressive, especially in light of the fact that we only spent $8,100 to build it, not including the parts from "X." The Engine
All that ground-pounding goodness came gratis some free-breathing induction from Trick Flow Specialties in the form of the new PowerPort 320cc aluminum heads, and R-Series single-plane intake manifold. Flowing over 360 cfm at its peak, the TFS PowerPort head could easily feed 502 hungry inches (now 509 with an overbore), but not alone. We got additional induction help from a solid-roller valvetrain from COMP Cams-principally by way of 292/298 degrees of gross duration (.020-inch tappet rise), 254/260 degrees duration at .050, and .653/.666 inches of lift. Finishing out the induction chores was a brand-new 1,150-cfm Ultra Dominator from Holley. Although the 502 Ramjet short-block we started with was endowed well enough for a touch over 500 hp, these new free-breathing pieces would put a hurtin' on the I-beam Ramjet connecting rods, so we elected to go with some stronger Eagle H-beam rods. Lastly, the Ramjet's low-compression pistons would have to be replaced in order to capitalize on the promising horsepower potential of the Trick Flow induction. We selected a cost-effective set of SRP 17cc domed pistons in a 4.500-inch bore size. With our stock crank, these would push our 502 up to 509 cubes and peg the compression at a comfy 10.1:1. The entire package was assembled with the aid of Andy Mitchell of Outlaw Racing Engines in Upland, California. Our 509ci Pile Driver big-block... Our 509ci Pile Driver big-block Chevy was built by Andy Mitchell of Outlaw Racing Engines in Upland, California. Last month, the potent solid-roller combo generated 717 hp (at 6,300 rpm) with 91-octane pump gas on the engine dyno. New heads and intake from Trick Flow Specialties, and a new Ultra Dominator from Holley were a large part of that equation. The Pile Driver big-block Chevy combo acquitted itself nicely on the Westech Performance dyno in Mira Loma, California, pumping out the aforementioned 717 hp on pump gas, with the timing set at 32 degrees total. Having met our goals for performance and cost, we were pleased with the results, which you can read about in more detail (along with the engine assembly) in the November 2009 issue. The Challenge
While hanging out at the dyno, we wondered just how much e.t. the 509 Pile Driver would be good for in a street car that was optimized for the track? It's a question we get asked a lot, especially when readers call bs on magazine dyno test results. As the saying used to go before the advent of Engine Masters, you can't race a dyno. We initially thought about dropping the Pile Driver into the Street Sweeper, our resident '68 Chevelle project car. With its bulletproof Currie 9-inch rearend, TCI Super Street Fighter Turbo 400 trans, and 28x10.5-inch Mickey Thompson slicks, it certainly has the driveline beefcake to handle the power, but without a rollcage, we'd be dead in the water. We have already been kicked out of the track twice for running quicker than 11.50 with the 496-inch Howitzer big-block, so they were on to us. What we needed was a car that was close to the Street Sweeper Chevelle in terms of weight, equipment, and driveline, but that was more optimized for the dragstrip than our g-Machine-oriented project car. We put the word out locally, and found our guinea pig through Tim Lee, owner of Don Lee Auto Service in Rancho Cucamonga, California. Lee got us in touch with Don Gatlin of Bakersfield, California, a 42-year-old electrical contractor, who has been bracket racing steadily for 20 years. Don liked the idea, and loaned us his '71 big-block Chevelle bracket racer that also does double duty as a street car. The Chevelle
Gatlin's Chevelle has been in his family for six years, being bracket raced for most of that time, while also seeing a good amount of street duty. Gatlin's '71 is a veteran of the regional Top Comp class, having racked up numerous wins and many appearances in the finals. Normally, his Chevelle has an iron-headed 540ci big-block underhood. That mill has 12.5:1 compression, iron Merlin heads, Merlin block, and a .730-inch lift solid-roller cam. Gatlin figures that engine makes around 850 hp, but he's never actually put it on the dyno. It has, however, powered the Chevelle to a best quarter-mile e.t. of 9.98/135 with a 1.45 60-foot time. That e.t. was with a curb weight of 3,730 pounds, including the driver. It's interesting to note that with the aluminum-headed Pile Driver 509 underhood (which also sported a much lighter 502 block), the curb weight dipped to 3,642 pounds with driver, for a savings of almost 100 pounds off the nose. With Gatlin's blessing, we enlisted the help of Tim Lee and the crew at Don Lee Auto Service to swap Gatlin's 540 Merlin for the Pile Driver. A few hours later, we hit the start button, and everything sounded perfect, just like it did on the dyno. We got to work swapping out... We got to work swapping out Don Gatlin's 540, and dropped in the 509ci Pile Driver. With the exception of chasing a different flywheel, it was an easy swap. Lots of credit goes to Tim Lee of Don Lee Auto Service for helping us locate the Chevelle, and wrangling the engines at the last minute. (Photo by Scott "Sticky" Miller) At The Track
In order to meet our deadline, we needed to get to the track soon. As luck would have it, there was a big bracket race scheduled for the following weekend on August 8 in Fontana. The thrash paid off, and we made it with a healthy car. Due to the huge number of racers, we would only be allowed one time trial, then go directly into bracket eliminations; so we'd get two runs for sure, and more if we were lucky. For the first run, Gatlin set the tire pressure at 10.2 pounds, based on his prior experience with the Chevelle. After a bigger than usual burnout (for the camera), Don launched the Pile Driver off the transbrake at 3,800 rpm, but after short wheelie, it stumbled, 60-footed with a 1.67, then picked up steam again. The lights showed an 11.23/124. The postmortem in the pits was that we forgot to install jet extensions in the rear metering plate. Fuel was sloshing away from the jets, causing a big bog. With jet extensions installed and a slight adjustment to the needle and seat of the rear float bowl, Gatlin went back for his first round of eliminations. We agreed to dial the car hard with a 10.60, hoping we'd feel good if we broke out. We had this one last chance, and the Pile Driver needed to produce! Without changing the setup to the tire pressure, shocks, launch rpm, or the 6,600-rpm shift point, Gatlin did his burnout, staged it, then let it fly. Once again, the front end stood up, but no bog this time. Everything sounded fine down track, and Gatlin lit up the scoreboard with a losing 10.608 at 128.46. Don redlit by two hundredths, but otherwise ran dead-on his 10.60 dial-in. Unfortunately, losing means we had no more runs left. Nevertheless, we got the TFS-equipped Pile Driver down into respectable 10-second territory, and proved that every pony we made on the dyno got put to the tire!  We were curious of exactly...  We were curious of exactly what kind of quarter-mile e.t. our 717hp big-block was worth, so we went looking for the perfect car to test it in, and discovered Don Gatlin's '71 Chevelle. Gatlin and his Chevelle are bracket racing veterans. "The car works," Don says. "That car's won
several bracket races and has been in the finals a lot." For the test, we pulled out his regular motor-an 850hp 540ci Merlin big-block.  Nested into Don Gatlin's '71...  Nested into Don Gatlin's '71 Chevelle, the Pile Driver looks like it belongs there. Gatlin's Chevelle is all business, and is optimized for the dragstrip. Note the chassis stiffener bars, electric water pump, crankcase evac system, and the lack of fender wells, or an HVAC unit. The battery has been relocated to the trunk, where it keeps a 15-gallon fuel cell company.  The rear suspension of Don...  The rear suspension of Don Gatlin's '71 Chevelle is frugal and effective. A Currie 9-inch rear loaded with a spool and 4.10 gears is managed by a pair of QA1 Stocker Star single-adjustable shocks (set on "7"), Moroso Trick springs, and an old set of Southside Machine lift bars. An Alston Chassisworks swaybar has some slight pre-load on the passenger side to give it some bite. Note the exhaust, which consists of four mufflers-two 4-inch Cherry Bombs, and two 4-inch single-chamber Flowmasters.  Don's Chevelle is mostly a...  Don's Chevelle is mostly a bracket race car, but it also does occasional duty as a street car. Two seats, working doors, and a full interior make it just tolerable. It's interesting to point out that Don's Chevelle is only a few pounds lighter than our Street Sweeper '68 Chevelle, in spite of much lightening throughout the car. The reason can be seen here: an extensive rollcage.  Before making the first run,...  Before making the first run, Gatlin checked the tire pressure and set it at 10.2 psi. Over the years, Don has found that to be an excellent baseline for his Chevelle, which wears 29.5x10.5W Mickey Thompson ET Drag slicks. As his regular engine-a 540-inch Merlin-makes over a 100 hp more than the Pile Driver, Don knew the Chevelle would launch predictably.  Back in the pits, we pulled...  Back in the pits, we pulled the secondary metering block off the Holley Ultra Dominator, and screwed in some jet extensions. The extensions put the jets at the rear of the float bowl where they can pick up fuel even under heavy acceleration. Obviously, on the dyno we didn't encounter any g-force, so it was never a problem before. The tune was dead-on, so we didn't touch the jetting.  On our one and only time trial,...  On our one and only time trial, the Pile Driver launched Gatlin's Chevelle nicely, then fell flat on its face, bogging at the top of First gear. The run wasn't a total bust, going over 124 mph through the traps (an 11.23 e.t.). Gatlin correctly diagnosed the problem as momentary fuel starvation.  Check out how air is fed to...  Check out how air is fed to the filter assembly via a cowl induction setup. This feeds high-pressure air to the carb from the base of the windshield. Note the momentary contact switch on the cowl where the induction base ends. These are great time-savers when adjusting valve lash or diagnosing problems.  At the first round of eliminations,...  At the first round of eliminations, we dialed-in the car hard with a 10.60. This was based on the 124-mph trap speed from our first run, which turned out to be dead-on. Gatlin set the MSD chip to 3,800 rpm, and launched on the transbrake for a 1.53 60-foot time. Shifting at 6,600 rpm, he ran a 10.608/128.46, but lost due to a .023 red light! The '68 Roadrunner in the other lane was sleeping at the Tree with a .200 light, and actually broke out. In bracket racing, it's first or worst-so Gatlin handed the win to the Mopar.
|
|
|