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.