COMP Cams 12-602-8 Big Mutha’ Thumpr Hydraulic Roller Camshaft Kit w/Redline HP Retro-Fit Lifters for Chevy SBC 283 305 327 350 400 Very Rough Idle - 243/257 @.050" .531"/.517" 107° LSA

Bring 21st-century performance technology to your classic engine with the Competition Cams 12-602-8 Big Mutha Thumpr Retro-Fit Roller Camshaft. This is the ultimate upgrade for Small Block Chevy (265-400ci) owners who want the earth-shaking sound of the "Big Mutha Thumpr" combined with the superior efficiency and reliability of a hydraulic roller valvetrain. Designed specifically as a Retro-Fit camshaft, this unit allows you to install a modern roller setup into older, non-roller engine blocks (pre-1987), eliminating the break-in risks associated with flat tappet cams while delivering smoother operation and significantly more horsepower. The specifications on the 12-602-8 are nothing short of radical. By utilizing a roller profile, Competition Cams is able to open the valves faster and lift them higher than a flat tappet cam ever could. It features a massive Duration @ .050 of 243 intake and 257 exhaust, paired with a high-performance valve lift of .533”/.519”. This geometry creates a monstrous power band from 2,500 to 6,400+ RPM, making it perfect for high-performance street/strip cars, hot rods, and pro-touring builds that demand top-end dominance. How does it feel? It is the perfect blend of violence and refinement. Thanks to the signature 107-degree Lobe Separation Angle (LSA), you get that brutal, heavy-loping idle that shakes the ground—exactly like a race car. However, because it is a roller cam, the engine runs with less friction and more responsiveness than a flat tappet equivalent. Warning: This is a serious performance part. The radical duration creates low vacuum, meaning you MUST run a high-stall torque converter (2,800+ RPM recommended) and performance rear-end gears (3.55-4.11) to unleash its full potential on the street. Why choose the 12-602-8? Because you are done with the anxiety of wiping out flat tappet cam lobes. Competition Cams engineered this Retro-Fit roller to be the last cam you ever need to buy for your build. It offers the legendary sound of the Thumpr series with the peace of mind that comes from modern roller technology. If you have the budget to upgrade your lifters and want the most powerful, loudest, and most reliable setup for your classic Chevy, the Big Mutha Thumpr Roller is the undisputed king of the street.

• LIFETIME WARRANTY IF INSTALLED BY A CERTIFIED MACHINIST
• Complete Street/Strip Cam & Lifter Kit – Includes Competition Cams 12-602-8 Big Mutha’ Thumpr hydraulic roller camshaft and Redline Performance Retro-Fit link-bar roller lifters for SBC engines (283–400).
• Correct Big Mutha’ Thumpr Specs – 243° intake / 257° exhaust duration @ .050", .531" intake / .517" exhaust lift, and a tight 107° Lobe Separation Angle produce massive airflow, high cylinder pressure, and the legendary choppy idle.
• Modern Retro-Fit Roller Technology: Designed for Gen 1 SBC blocks (pre-1987), this cam brings modern efficiency to vintage engines. Why Buy It: It drastically reduces internal friction and completely eliminates the risk of "wiping a lobe" during break-in, offering superior longevity compared to flat tappet cams.
• Radical "Race Car" Sound (107 LSA): Featuring a tight 107-degree Lobe Separation Angle, this cam delivers the trademark Big Mutha Thumpr heavy-lope idle. Why Buy It: It guarantees maximum intimidation factor, giving your street car the audio profile of a high-compression dragster.
• High-Lift Roller Geometry (.533”/.519”): With a substantial lift of .533” Intake and .519” Exhaust, this cam takes full advantage of the roller design to open valves aggressively. Why Buy It: It provides significantly more area under the lift curve than a flat tappet cam, resulting in greater horsepower and torque gains across the entire 2,500-6,400 RPM range.
• Engineered by Competition Cams: This is a premium steel billet hydraulic roller cam. Why Buy It: It is built to handle high spring pressures and high RPMs. Installation Note: Requires the use of Retro-Fit Hydraulic Roller Lifters and a thrust button/plate setup; standard flat tappet lifters will not work.
• Trusted COMP & Redline Quality – Engineered for stability, durability, and proven horsepower gains backed by two of the most respected names in performance.