When it's all said and done, it's about the power. Almost 12 years ago, Lingenfelter Performance Engineering (LPE) built us a 420ci small-block track-day warrior. This is an interesting 4.155-inch bore and 3.875-inch stroke combination that was intended to maximize torque and horsepower between 3,000 and 6,000 rpm with an emphasis on torque. To this end, it made 525 hp and 540 lb-ft of torque all below 6,000 rpm. It worked so well, we've taken to calling this engine Brutus. It went into our much-abused '65 Chevelle, and we planned to run it hard, so it had to be durable. Toward this end, Lingenfelter spec'd some great parts including a Bow Tie iron block containing a 4340 forged steel Crower crank and rod rotating package, Air Flow Research 195cc heads, and an ACCEL/DFI electronic fuel injection system using the ACCEL/DFI SuperRam intake.
Lube It Or Lose ItDespite Brutus' size, we initially chose to run a stock-type oil pan with a mundane '69 Z28-style windage tray. This worked fine at first, but chassis mods and gumball tires have created sufficiently high lateral g's to push the oil right out of the sump, causing oil cavitation problems. After a tour through the Moroso catalog, we decided on a kick-out, road-race style pan that would give us some much-needed oil control and still clear the Chevelle's steering linkage. In the January issue, we backyard-tested this oil pan ("Slip-Slidin' Away," Jan. '04, pg. 38). While the testing was backyard crude, it did reveal that the Moroso pan was capable of oil control far superior to the stock pan and windage tray.
In the car, the engine is also equipped with an external filter and an Earl's water-to-oil cooler, but even with these additional components, we decided to stick with a standard volume, standard-pressure Moroso performance oil pump. The reason for this is to minimize the parasitic losses through the path the oil has to travel. The oil cooler is an essential part of this combination since even just three or four full-tilt blasts around a road course can send engine oil temperature soaring close to 275 degrees or higher if not controlled with a cooler. In fact, the conservative Earl's cooler we're using is actually a bit too small for even this 500hp small-block.
Finally, we fully intend to run pure synthetic oil in the 420, and we may test a couple of different oils in the near future. Castrol, Lucas, Mobil 1, and many other companies offer pure synthetics that have the temperature stability to handle 275-to-300-degree oil temperatures that are almost commonplace for track-day excursions. Synthetic engine oil is an absolute requirement for track days if you're not running an oil cooler.
Induction NoticeFor the other half of our effort, we decided it was time to retire the original Gen VI ACCEL/DFI injection package that had powered our small-block for so many years. The system worked great, but DFI engineer Joe Allamandine promised us a much better resolution with the new Gen VII system. While intended to run as a sequential fuel injection system, we decided to do our comparison testing in batch fire to reduce the initial variables and to quickly get acquainted with the new system. Later, we can look at the advantages of converting to sequential. Just converting to the Gen VII system promised more finite control over the fuel and spark and the potential for wide-open throttle feedback control using a wide-band oxygen sensor.
The most dramatic personality change for Brutus was the switch to ACCEL/DFI's impressive Lingenfelter-designed single-plane multipoint EFI manifold. In a quickie test several months ago, we learned just how strong this manifold is. Since the original SuperRam-equipped Brutus made more torque than we could use on the road course, we decided to trade a little torque off the bottom for more horsepower by using the new single-plane intake. We were hoping for an increase of 15 to perhaps 20 more hp from these new parts, but we got much more.
Dyno Test DayOnce our dyno guy Ed Taylor had the 420 up on the dyno, it only took a few minutes to create a basic fuel curve using the ACCEL Gen VII's configuration software after inputing the engine's size and camshaft information. The engine instantly fired up and idled, and it wasn't long before we were making power. This engine does sport 11:1 compression, but even with aluminum heads and this healthy Comp cam, we had to mix 50 percent 100-octane unleaded with our 91-octane premium pump gas to allow the engine to run at its maximum ignition timing.
Taylor initially configured the 420 with the ACCEL four-barrel style throttle-body that actually cranked out a respectable 537 hp and 528 lb-ft of torque. Then we tried the larger three-barrel throttle-body and picked up a little power-up to 546 hp and 532 lb-ft. Then we tried the largest rated throttle-body, and the power jumped yet again, this time to an astounding 560 hp at 6,200 and 547 lb-ft at 4,600 rpm. We were hoping to pump the power up by 15 or perhaps 20 hp, but this killer ACCEL intake ramped up our horsepower increase a total of 35 hp while the torque peak moved around some, but actually increased slightly!
ConclusionOverall, we were thrilled with our competition-proven Brutus 420ci small-block. Considering what this engine has been through, to make 560 hp with this kind of durability is outstanding. Granted, this is hardly a budget exercise. But it also proves that purchasing quality parts and assembling the engine properly always proves to be worth the money invested. Just for fun, we plugged the 560hp power curve into the Quarter Pro dragstrip simulation program using a 3,600-pound Chevelle with a TH-400 trans, medium sticky 26-inch-tall tire, 3.55:1 gear, 3,000-rpm stall converter and were surprised at the 11-teen e.t. and the 120-mph-plus trap speed. That's what displacement and a solid torque curve will give you. Oh, and the horsepower helps too
Cam SpecsWhen this engine was originally built, Lingenfelter chose the original specs list in the first cam. The latest version of this cam is the XR 286. We decided not to change cams, but note that for the same advertised duration, the Xtreme cam offers more duration at 0.050 and greater lift on both the intake and exhaust sides. This would probably mean a little more horsepower without sacrificing torque. We are also using 1.6 rockers, which bumps the lift another 0.035 inch.
Camshaft Duration Duration Lift Lobe (Advertised) @ 0.050 (inches) Separation SR288 Int. 280 236 0.550 110 Exh. 288 244 0.550 XR286 Int. 280 242 0.570 110 Exh. 286 248 0.576
Power By The NumbersOur original LPE-built 420ci small-block was fitted with an ACCEL/DFI SuperRam intake manifold. In that configuration, the engine produced a respectable 525 hp at 5,500 rpm and a peak torque of 542 lb-ft at 4,500.
Test 1 is the 420ci fitted with the ACCEL intake and four-barrel throttle-body.Test 2 is the same configuration except with the larger three-barrel throttle-body.Test 3 is the same configuration except with the monster two-barrel throttle-body.
TEST 1 TEST 2 TEST 3 RPM TQ HP TQ HP TQ HP 3,000 500 286 503 289 516 295 3,{{{200}}} 506 308 {{{505}}} 308 521 317 3,400 508 329 514 333 525 340 3,{{{600}}} 508 348 515 353 523 358 3,800 506 365 512 370 521 377 4,000 513 391 520 396 530 403 4,200 516 413 521 417 534 427 4,400 521 436 526 440 541 453 4,600 525 460 530 464 547 478 4,800 528 483 532 486 546 499 5,000 523 498 531 505 543 517 5,200 517 512 527 522 538 533 5,400 507 522 516 530 531 545 5,600 502 535 506 540 522 557 5,800 486 536 494 546 506 559 6,000 470 537 475 543 489 558 6,200 454 535 456 539 474 560 6,400 431 526 437 534 447 545Details, DetailsLately we've been interested in how much power the engine makes in the car. Often the engine is equipped differently in the car from the way it was tested on the dyno. Prior experience has shown that little details, especially at over 550 hp, can have a big effect on power. One thing we tried was to bolt on a 4-inch-tall, 14-inch-diameter air cleaner to see if it would cost power. Our first hurdle was that most of our carbureted air cleaner bases hit the ACCEL fuel rails. We found a relatively flat 14-inch-diameter base that cleared the rails, but it interfered with the throttle linkage. To make it clear, we added a 1-inch-tall spacer between the throttle-body and the air cleaner base, which immediately cost us 10 hp. We discovered that by maintaining the radius from the air cleaner base into throttle-body (or carburetor), the power came right back.
If you look closely at the two photos, there is a gentle radius in the air cleaner base that matches nicely with the beginning radius of the throttle-body. When the spacer is added underneath the air cleaner base, this disrupts this radius, leading to turbulence entering the throttle-body and lost power. We're not sure how this would relate to a carburetor at the same power level, although its possible the same thing could occur. Remember that this is strictly an airflow issue, since fuel is introduced farther downstream. It's also possible that there could be power losses associated with an adapter like this, even at 400hp levels. Just like everything else in life, it's the details that make the difference.
Parts List Component Manufacturer Part Number Block GMPP 12480157 Crank Crower 95127 Rods, billet Crower B93002 Pistons, forged Ross 99473 Cam, Xtreme 286 Comp Cams 12-771-8 Lifters, mech. rollers Comp Cams 818-16 Rocker Arms, Hi-Tech Comp Cams 1105-16 Cyl. Heads, 195cc AFR 1038 Intake, EFI, bare ACCEL/DFI 74140 Intake, EFI w/750 TB ACCEL/DFI 77141 Intake and fuel rails ACCEL/DFI 74139 Throttle-body, 1,000 cfm ACCEL/DFI 74202 Throttle-body, 1,{{{200}}} cfm ACCEL/DFI 74202S4 Throttle-body, 1,350 cfm ACCEL/DFI 74202S3 Throttle-body, 1,550 cfm ACCEL/DFI 74202S2 Injectors, 36-lb/hr ACCEL/DFI 150136 EFI-DFI Gen VII ACCEL/DFI 77040 Headers, 131/44-inch Hooker app. specific Oil pan Moroso 21900 Oil pump, std. vol. Moroso 22100 Oil pump pickup Moroso 24170 Valve covers Moroso 68326 Fuel pump, EFI Aeromotive 11106 Fuel pressure regulator Aeromotive 13105