The term 30-30 is a reference to the solid-lifter cam’s valve lash settings assigned by Chevrolet. LIFT: The cam's basic function is to open the valves. LOBE SEPARATION ANGLE: This is the relationship between the centerlines of the intake and exhaust lobes. Low 14's was the result. If you didn't figure it out or did but still aren't sure exactly why the cam is wrong, you need to read the following. One of the endeared characteristics of mechanical cams is that signature tapping of the valvetrain. Piddle-Valve lifters are solid lifters and were used in production engines. Billy explains, “There is a Comp Cams series of cams called the “Nostalgia Plus” series that match the opening and closing ramp rates and valve timing events of the original cams. The 30-30 cam is a solid lifter performance camshaft, but is an entirely different camshaft altogether from the “097” Duntov cam. Just like setting the ignition timing, valve lash has certain recommendations from a camshaft’s manufacturer, but ultimately, it comes down to the particular application and expectations of the end user. A 280 cam (advertised duration) from one manufacturer could actually have less at-.050 duration than a 278 cam from another, due to the different points at which the companies measure advertised duration. In the case of the smaller 327, the L79 was essentially a solid-lifter L76 (365-hp 327) with a cam swap. General Motors produced the L79 from 1965 to 1968. Mushroom lifters used their larger base diameter for yet more agressive cams and the Edge-Orifice lifters reduced oil flow to the requisite roller rockers to control oil starvation at high rpm. The Duntov cam was a predecessor to many of these designs. This is due to many reasons. The reason it became the 30-30 cam is because it ran so much better with the lash opened up to .030-inch hot. Today you even have the option of converting over to a hydraulic or solid roller valvetrain. (Used with permission, GM Media Archives). Chevy Hardcore NEWSLETTER - SIGN UP FREE! If yours is close to one of them, choosing one of the cams recommended will guarantee happiness. UNDERSTANDING CAMSHAFT SPECIFICATIONS There are many numbers and terms used when describing a camshaft's design that must be understood when choosing a cam. In the early to mid-fifties, horsepower wars were just getting fired up, and aspiring racers and engineers were burning the midnight oil trying to figure out a way to get an upper hand against the cross-town competition. So, it was in 1965 that the hot hydraulic cam, L79 327 engine first appeared in the Corvette and the Chevelle. These cams have become the benchmark for 5th Gen Camaro’s and C6 Corvette’s all over the country. This made him a prime target for those within GM that didn’t share his enthusiasm for speed. Notes: Notice the differences between advertised duration and .050 duration. All camshafts meet original Corvette specifications. Roller cams, which we'll discuss below, have the advantage of allowing high rates of lift with relatively short duration. Aside from the "juice" cam, it was a mechanical copy of the Corvette's L76 and shared the same forged 11.1:1 pistons, 585-cfm 4150 series Holley … https://www.chevyhardcore.com/tech-stories/engine/duntov-small-block- Notes: Comparing this example to Vehicle 1 shows the effect that displacement has on cam timing. The "097" cam was used in 327's in '62 and '63 (340hp carbed and 360hp fuelies) in addition to the 2x4 and fuelie 283 applications from '57 through '61. Car is 80-percent street, 20-percent strip. Once this is determined, the following important details must be taken into account to get exactly the right camshaft: the engine's compression ratio, the basic power range of the heads/intake manifold/carb/headers combination, the car's weight, the transmission type (and/or torque converter stall speed), the rear gear ratio and the rear tire size. The 30-30 cam was designed for the cross-ram 302 in the Camaro Z/28, which still used cast manifolds in stock form. RECOMMENDATIONS FROM THE PROS Please tell me what you think was available in the corvette line? 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The quicker action also worked great to minimize seat timing without dramatically reducing area under the curve. Andy has been intrigued by mechanical things all of his life and enjoys tinkering with cars of all makes and ages. The L79 was essentially the solid-lifter L76 (365-hp 327) with a cam swap. Other Stuff You'll Need: Never reuse old lifters with a new cam, even if they've only been run for five minutes. Lifters and cam lobes develop a unique wear pattern almost immediately that won't be compatible with a new camshaft. L76 327 Small-Block. Perhaps use the cam that is used in this article L84 Fuelie Motor On Engine Dyno - Vette Magazine - View All Page My Father bought a crate L76 327 (same longblock as fuelie 375hp L84, just rated at 365hp with a 4bbl). At this looser lash setting, the system was accelerating though the lash take-up, thereby keeping everything in compression. Notes: Compare the grinds for this 302 with Vehicle 2, the 350 Chevy with a 2400-stall converter. He keeps his feet firmly grounded by working on his two street rods and his supercharged C4 Corvette. But, other than the fact that a modern SBC camshaft looks kind of similar and has many of the same overall dimensions, almost nothing is left over from those 50+ year old designs.”. Often referred to as the Duntov "30-30" design. His passion (and some of his antics) are legendary around the halls of General Motors, and often, his passion for performance wasn’t shared with the upper brass at GM or Chevrolet. The motor that met those specifications was given the L79 sales code and put out an impressive 350 horsepower. “That said, I cannot think of a good reason to run a Duntov camshaft in any non-restoration package, as you are immediately giving up more than 50hp due to the lazy valve events and low area under the curve.” While the Duntov cam is/was considered to be a performance cam, there is good reason why we might not want to consider it the end-all for performance. Zora Arkus-Duntov was a car guy’s car guy. As various components within the engine heat up independently, they expand at different rates. This is ground into the cam and can't be changed without changing cams. An engine that suffers these driveability headaches and still gets blown away by a Chevette is the worst possible hot rodding experience.

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