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Combo 75.
Combo 75 uses the same block as Combo 74, but Trick Flow street heads and a bigger cam is used. The heads are not the Twisted Wedge versions from Trick Flow, but heads that are designed as direct factory replacements. To help the heads flow better, a more aggressive camshaft is also used. The upgrade increases the power by 43 HP and the torque by 31 ft-lbs. With this cam and heads, the torque peak occurs at a more normal 79% of the HP peak. |
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Displacement: |
355 cu. in. |
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Carburetor: |
Demon Speed Demon 750 |
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Heads: |
Trick Flow 23° Street Heads, with 2.02/1.60 in. valves and 195 cc intake runners |
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Intake: |
Edelbrock Performer RPM |
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Camshaft: |
Comp Cams 286 Magnum hydraulic, with 286° of duration, 236° of duration @ 0.050 in. of lift and 0.490 in. of lift. |
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Exhaust: |
Hooker Super Competition headers with Flowmaster 3 in., 3-chamber mufflers |
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Pistons: |
Federal-Mogul forged aluminum |
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Rods: |
stock |
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Crank: |
cast |
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Comp. Ratio: |
9.4:1 |
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MAX HP: |
423 @ 6200 |
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MAX Torque: |
417 @ 4900 |
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Combo 76.
Combo 76 comes from pages 125-130 of the July 2000 issue of Super Chevy. It uses all-Edelbrock components with 8.5:1 compression to make 310 HP and 378 ft-lbs of torque. |
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Displacement: |
350 cu. in. |
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Carburetor: |
Edelbrock Performer 600 |
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Heads: |
Edelbrock Performer, with 2.02/1.60 in. valves and a 3-angle valve job |
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Intake: |
Edelbrock Performer |
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Camshaft: |
Edelbrock hydraulic, with 204/214° of duration @ 0.050 in. of lift, and 0.420/0.442 in. of lift. |
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Exhaust: |
shorty 1 5/8 in. headers and dual pipes |
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Comp. Ratio: |
8.5:1 |
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MAX HP: |
310 @ 5000 |
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MAX Torque: |
378 @ 4000 |
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Combo 77.
Combo 77 comes from pages 64-67 of the April 1991 issue of Chevy High Performance.
Combo 77 uses a 350 cu. in. engine with reworked GM #186 heads and a Comp Cams 268° camshaft. The source states that the camshaft has 0.474 in. of lift—however, the Comp Cams High Energy 268° cam only has 0.454 in. of lift, and the Comp Cams Xtreme Energy 268° cam has 0.477 in. of lift. Perhaps Comp Cams used to offer this version back in '91. Anyhow, this combination makes 383 HP and 404 ft-lbs of torque. |
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Displacement: |
355 cu. in. |
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Carburetor: |
Holley 650 |
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Heads: |
GM #186, with 2.02/1.60 in. valves, reworked 160 cc intake runners, and bowl blending |
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Intake: |
Edelbrock Victor Jr. |
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Camshaft: |
Comp Cams 268, with 268° of duration and 0.474 in. of lift |
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Rockers: |
Comp Cams 1.6:1 Magnum roller |
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Exhaust: |
1 3/4 in. headers, a crossover pipe, and Cyclone Sonic turbo mufflers |
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Pistons: |
Sealed Power forged |
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Rods: |
stock |
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Crank: |
cast |
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Timing: |
34° |
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Comp. Ratio: |
10.5:1 |
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MAX HP: |
383 @ 5250 |
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MAX Torque: |
404 @ 4100 |
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Combo 78.
Combo 78 comes from pages 65-68 of the April 2001 issue of Chevy High Performance.
GM Vortec cylinder heads are used with a Comp Cams Xtreme Energy 262° camshaft to produce 390 HP and 426 ft-lbs of torque. These numbers are made with 87 octane, while most of the combos on my site used 92 or 93 octane gasoline. Again, I am not sure how much of a power difference the lower octane makes. |
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Displacement: |
355 cu. in. |
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Carburetor: |
Demon Road Demon 625 |
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Heads: |
GM L31 Vortecs, with 1.94/1.50 in. valves |
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Intake: |
Edelbrock Performer RPM Vortec |
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Camshaft: |
Comp Cams Xtreme Energy 268° hydraulic, with 268/280° of duration, 224/230° of duration @ 0.050 in. of lift and 0.477/0.480 in. of lift.(Corrected valve lift with 1.6:1 rockers is 0.508/0.512 in.) |
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Rockers: |
Comp Cams roller, 1.6:1 |
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Headers: |
Hedman Elite 1 5/8 in. |
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Pistons: |
Speed Pro dished |
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Rods: |
stock |
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Crank: |
Scat |
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Distributor: |
Pertronix HEI |
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Timing: |
36° |
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Comp. Ratio: |
8.75:1 |
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MAX HP: |
390 @ 6000 |
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MAX Torque: |
426 @ 4000 |
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