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15 Dyno-Proven Horsepower Combos

Rear-Wheel Dyno Combos

Photography by Marko Radielovic

Every year we plant ourselves at the Castrol Syntec/Werx Motorsports mobile chassis dyno at the Car Craft Summer Nationals to observe our readers' cars on the chassis dyno. This year we also staked out the dyno at the Street Machine Nationals in Lima, Ohio, to broaden the scope of this article. A wide variety of cars, engines, and combos made their way to the rollers to prove their mettle. Keep in mind that these are real-world numbers subject to a whole slew of outside factors that affect horsepower. It should be no surprise that the Midwest is quite hot and humid during the summer, so power output was significantly lower than it would have been on a cool Fall morning. That said, at least all who participated were subjected to the same handicaps.

Now before we get letters from the AMC/Ford/fill-in-the-blank faithful about bias, we camp out at the dyno during the entire event, and we can only document the vehicles that actually step up. We avoided the high-compression participants, as we felt they weren't a reflection on the typical street combinations that the average guy would screw together. So sit back and take note of how much power the real world is cranking.

Pontiac: Mild

Car: '68 Pontiac GTO
Owner: Guy Hiney

Guy Hiney of Anoka, Minnesota, has proven that the 400ci Pontiac can be a contender with the right bolt-ons. Though his Goat pumped out less than he had hoped, 313 hp at the wheels is nothing to be ashamed of, and it's better than many larger and more radical combinations we've encountered. Guy's 0.030-over 400 has been outfitted with a 292H Comp hydraulic cam, a set of roller rockers on stock Pontiac head castings, and an Edelbrock Performer RPM intake with a 750-cfm Quadrajet. It just goes to show that Pontiacs, like all other American V-8s, respond to the usual performance upgrades.

Engine

Type: Pontiac V-8
Displacement: 406 ci
Compression: 10.0:1
Best e.t.: 13.0

Heads

Make and model: Production iron
Port work: None
Valve sizes: 2.11/1.77 inches
Rocker arms: 1.52:1 roller

Camshaft

Make: Comp Cams
Type: Hydraulic flat-tappet
Duration at 0.050: 244 degrees
Valve lift: 0.501 inch

Induction, Ignition, and Exhaust

Intake: Edelbrock Performer RPM
Carburetor: Q-jet
Ignition: Pertronix
Exhaust: 1 ¾-inch headers, 2 ½-inch dual exhaust

Performance

Owner's guess: 355 hp
Dyno result: 313 hp, 362 lb-ft

Oldsmobile: Wild

Car: '84 Hurst Olds
Owner: Gary and Cindi Valland

This '84 Hurst Olds owned by Gary and Cindi Valland surprised us all. While it sounded nasty, we weren't prepared for the nearly 400 rear-wheel horsepower or the nearly 500 lb-ft of torque. In California where we are strangled with emissions laws, we don't expect a "late model" to sound quite like the Valland's Oldsmobile. The Edelbrock aluminum cylinder heads are undoubtedly responsible for a good portion of this Rocket's 384 hp, as is the long-duration Camotion solid grind. Up top, Gary perched an Offy Portosonic intake and a Holley 780 Street Avenger carb. The often-overlooked Oldsmobiles are truly capable of outstanding performance with the right combination of parts.

Engine

Type: Oldsmobile V-8
Displacement: 468 ci
Compression: 10.5:1
Best e.t.: Unknown

Heads

Make and model: Edelbrock Performer RPM, aluminum
Port work: Fully ported
Valve sizes: 2.19/1.68 inches
Rocker arms: 1.5:1 rollers

Camshaft

Make: Camotion
Type: Solid flat-tappet
Duration at 0.050: 252/260 degrees
Valve lift: 0.576/0.566 inch

Induction, Ignition, and Exhaust

Intake: Offenhauser Portosonic
Carburetor: Holley 780-cfm Avenger
Ignition: MSD distributor with MSD 6AL
Exhaust: 17/8-inch headers, 3-inch dual exhaust

Performance

Owner's guess: 400 hp
Dyno result: 384 hp, 480 lb-ft

GM LS1: Mild

Car: '00 Pontiac Trans Am
Owner: Mark Heid

The reason for including a late-model LS1 in this article is simple. In a world of high-tech overhead-cam engine technology, GM has built another pushrod motor, and an outstanding one at that. With a few basic modifications, the LS1 will deliver the goods--period. Mark Heid and fiance Bridgette's Pontiac Trans Am, like many across the U.S., has been bolstered with what amounts to computer mods and an exhaust system and that's it. It still cranked out well over 300 hp at the wheels. The LS1 is the next-generation Mouse, with a plethora of aftermarket companies developing quality speed parts to make the already stout performers even faster. Who says pushrod engines are dead?

Engine

Type: GM LS1 V-8
Displacement: 346 ci
Compression: 10.0:1
Best e.t.: Unknown

Heads

Make and model: Stock aluminum
Port work: None
Valve sizes: 2.00/1.55 inches
Rocker arms: Stock 1.7:1 rollers

Camshaft

Make: Stock
Type: Hydraulic roller
Duration at 0.050: Stock
Valve lift: Stock

Induction, Ignition, and Exhaust

Intake: Stock
Carburetor: Stock throttle-body
Ignition: Stock with Hypertech programmer
Exhaust: Stock manifolds, after-cat aftermarket system with cutouts

Performance

Owner's guess: 340 hp
Dyno result: 326 hp, 335 lb-ft

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