Genuine COMP CAM 12-602-4 Big Mutha Thumpr 243/257 Camshaft | LIFT: .500/.486" | High-Performance Lifters | Double Roller Timing | Push Rods | Kit FITS Chevrolet SBC 283 327 350 400 5.7 5.7L

This is it—the King of the Thumpr series. The Competition Cams 12-602-4 Big Mutha Thumpr is designed for the Small Block Chevy (265-400ci) owner who refuses to compromise. If the "Mutha" was loud, the "Big Mutha" is earth-shaking. This camshaft delivers the most powerful, rough, and aggressive idle profile available in a hydraulic flat tappet design. It is engineered for street/strip machines, pro-touring builds, and hot rods where the goal is to sound exactly like a high-compression solid roller drag car, but with the maintenance-free reliability of a hydraulic setup. The specs on the 12-602-4 are massive. Competition Cams engineered this grind with a staggering Duration @ .050 of 243 intake and 257 exhaust, paired with a valve lift of .498”/.483”. This huge duration, combined with the signature tight 107-degree Lobe Separation Angle (LSA), creates an incredible amount of overlap. This doesn't just make noise; it creates a high-RPM power band that screams from 2,500 to 6,400+ RPM. This cam is designed to breathe deep at the top end, making it the perfect choice for 383 Strokers and 400ci engines that need to move serious air. How does it feel? Violent. The idle is radically choppy and will shake the fenders of your car. This is not a subtle upgrade; it changes the entire DNA of your vehicle. On the street or strip, the power hits hard in the mid-range and keeps pulling long after other cams have signed off. Warning: This is a serious performance cam. It has very little engine vacuum and ABSOLUTELY REQUIRES a high-stall torque converter (2,800+ RPM stall recommended), lower rear-end gears (3.55-4.11), and performance exhaust to run properly. Do not attempt to run this with a stock converter! Why buy the Big Mutha Thumpr? Because you want to dominate the car scene. Competition Cams built this for the enthusiast who wants maximum attitude. You are getting a precision-engineered component that allows you to run with the big dogs at the drag strip while still being able to drive to the track. If you have the compression, the gears, and the converter to support it, the Big Mutha Thumpr offers the most intense sound and top-end performance dollar-for-dollar on the market today.

• Maximum "Pro-Street" Sound (107 LSA): Featuring the aggressive 107-degree Lobe Separation Angle and massive overlap, this cam produces a radical, earth-shaking idle. Why Buy It: It is the closest you can get to the sound of a 900-horsepower race engine while still using a hydraulic flat tappet system. It guarantees you are the loudest car at the show.
• THIS LISTING WILL INCLUDE:
• 1)AUTHENTIC COMP CAM 12-602-4 BIG MUTHA THUMPR 243/257 HYDRAULIC CAMSHAFT - Hydraulic Flat Cam for Chevrolet Small Block 262-400. Street/strip, needs 9.5:1 compression, 2800+ stall, intake gears and headers, very rough idle.
• 16) ENGINETECH HIGH-PERFORMANCE HYDRAULIC LIFTERS
• 1) 3-PC DOUBLE ROLLER TIMING SET - True double roller. 3 key crank sprocket. 4 degree crank offset.
• 16) PUSH RODS - 7.794" Length
• High-RPM Dominance (243/257 Duration): With a massive 243 Int / 257 Exh Duration @ .050”, this cam is built for top-end speed. Why Buy It: It shifts the power band to 2,500-6,400 RPM, making it a lethal weapon for drag racing or high-performance street driving in lighter vehicles with deep gears.
• Near-.500 Lift Geometry (.498”/.483”): The lift is pushed to the limit of flat tappet reliability at .498” Intake and .483” Exhaust. Why Buy It: This aggressive lift maximizes the potential of ported iron or aftermarket aluminum cylinder heads, ensuring your engine gets the airflow it needs to make big horsepower numbers.
• Competition Cams Engineering: Designed for Gen 1 SBC V8s, this is the flagship of the Thumpr flat tappet line. Why Buy It: You get race-winning technology for your street car. Critical Fitment Note: Due to the radical duration, this cam produces low vacuum. You MUST use a 2,800+ stall converter and gears; a vacuum canister may be needed for power brakes.