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Supercharged 496 Motor - Long Rod Rat

Build The Ultimate Torque Monster-A Stroked, Supercharged 496.

DYNO CHARTS
RPM TQ HP
3500 639.9 426.4
3600 626.2 429.2
3700 623.8 439.5
3800 624.0 451.5
3900 635.9 472.2
4000 652.1 496.6
4100 694.3 542.0
4200 702.3 561.5
4300 746.3 611.0
4400 785.5 658.1
4500 797.2 698.2
4600 806.4 721.6
4700 815.1 745.0
4800 836.7 780.6
4900 832.5 806.2
5000 826.3 818.5
5100 814.0 833.1
5200 801.8 844.6
5300 787.2 855.2
5400 772.8 853.4
5500 759.4 848.0

Our first pulls on the Jim Grubbs Motorsports dyno were intended to squeeze maximum yield from the long rod 496. We locked the timing in at 30-degrees, put the small pulley on the blower, and filled the fuel tank with 110-octane race gas. After a few pulls, we found that 80 jets in the primaries and 86 jets in the secondaries worked best, and the boost gauge was peaking at 12.5 pounds. That's a lot of boost, but the numbers made our jaw drop. The torque curve was nearly flat, running over 600 lb-ft from 3,000 rpm to redline, with a peak of 836.7 lb-ft at a relatively high 4,800 rpm. Power doubled from 3,500 to 5,300 rpm, where it peaked at 855.2 hp.

RPM TQ HP
3500 578.0 385.2
3600 584.0 400.3
3700 587.9 414.2
3800 592.8 428.9
3900 595.0 441.8
4000 605.8 461.4
4100 623.4 486.7
4200 632.0 505.4
4300 626.8 513.2
4400 631.8 529.3
4500 640.9 549.1
4600 671.1 587.8
4700 674.0 603.2
4800 680.6 622.0
4900 688.6 642.4
5000 682.4 649.7
5100 675.2 655.7
5200 666.9 660.3
5300 662.9 669.0
5400 652.7 691.7
5500 647.1 698.6
5600 639.5 690.4
5800 618.0 678.2

Our second setup of the day was a more conservative setup. The big blower pulley was bolted on, which produced a significantly more conservative 5.5 pounds of boost. We swapped in 78 and 82 jets for optimal air/fuel, and dialed the timing back to 28 degrees. The fuel tank was drained and filled with 91-octane gas from the corner station. While not as awe-inspiring as the race-gas figures, the motor still made well in excess of 500 lb-ft of torque throughout nearly the entire rpm range, with a peak of 688 lb-ft at 4,900 rpm. Horsepower peaked at nearly 700 at a relatively low 5,500 rpm. Overall, running the engine in pump gas trim lost 157 horsepower and 148 lb-ft of torque, but with average numbers in the high 500-range, this mill could still propel a well-prepped street car into the 10s on pump gas.

SOURCES
Automotive Racing Products (ARP)
531 Spectrum Circle
Oxnard
CA  93030
805-278-7223
Lunati (A Division of Holley)
N/A
N/A
lunaticamshafts.com
Aviaid Oil Systems Slover's Porting Service
Cometic Gasket, Inc. Weiand (a division of Holley)
Bowling Green
KY
2-70/-781-9741
weiand.com
Holley Performance Products
1801 Russellville Rd.
Bowling Green, KY 42101
KY  42101
270-782-2900
www.holley.com
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