Mutha Thumpr Retro-Fit Hydraulic Roller Camshaft Complete Kit Lift: .522"/.509"
InfoVehicle Info Needed
COMP CAMSPART NUMBER: 249-K12-601-8

Mutha Thumpr Retro-Fit Hydraulic Roller Camshaft Complete Kit Lift: .522"/.509"

$1,83395
ShippingShips on 10/20/2026
Lowest PriceLowest Price Guarantee

Chevy 262-400ci Small Block 1958-98 Non-Factory Roller Block
  • Mutha Thumpr
    • Mutha Thumpr Retro-Fit Hydraulic Roller Camshaft Complete Kit
    • Lift: .522"/.509"
    • Duration: 291°/311°
    • Lobe Separation Angle: 107°
    • RPM Range: 2200-5900

      Valve Setting: Intake - Hyd, Exhaust - Hyd
      RPM Operating Range: 2200 to 5900
      Cam Grind Number: 291THR7
      Duration Advertised: Intake - 291, Exhaust - 311
      Duration @ .050': Intake - 235, Exhaust - 249
      Valve Lift: Intake - .521, Exhaust - .507
      Lobe Sep. Angle: 107°

      265, 283, 307, 302, 305, 327, 350, 383, 400, 427, L46, L48, L65, LM1, LT-1, L82, L81, LS9, L83, L98, L05, LG3, LG4, LT1, LT4, Camaro, Corvette, Chevelle, Stingray, Silverado, C10, Firebird, Chevrolet, Chevy, Small Block Chevy, Caprice, Malibu, Impala, Nova, 355, GEN1, Monte Carlo, S10


      High performance street/strip, needs 9:1 compression, 2500+ stall, intake, gears and headers, rough idle.

    Emissions Note:

    This part is only legal for sale and use on Uncontrolled (Non-Emissions Controlled) Vehicles or on vehicles used solely for the purposes of closed competition racing.

    CLICK THIS LINK FOR IMPORTANT CARB & EPA EMISSIONS INFORMATION ABOUT THIS PART

      Peak Power & Reliability

      The Thumpr line of camshafts is a series of retro-fit hydraulic roller camshafts designed for use in 1955- 1998 262-400 cubic inch Small Block Chevrolet engines equipped with flat tappet camshafts. Thumpr Camshafts possess such an aggressive exhaust note due to the lobe profiles and grind characteristics chosen by the COMP Cams engineers. These camshafts produce a combination of early exhaust valve opening, long exhaust duration, and a generous amount of intake and exhaust overlap to maximize the rough-idling characteristics. Their cutting-edge hydraulic roller design will deliver a substantial power increase over an identical hydraulic flat tappet grind without sacrificing reliability or ease of maintenance. So look no further than the Thumpr line of camshafts - engineered to deliver that much sought-after ''thumping'' idle quality to Small Block Chevy owners everywhere.

      Show More

      Camshaft & Lifter Kits are indicated by a CL in their part number and include Camshaft, Lifters, Assembly Lube, Decals, and Instructions.

      Complete Kits are indicated by a K in their part number and include Camshaft, Lifters, Timing Chain & Gears, Valve Springs, Retainers, Locks, Assembly Lube, Decals, and Instructions.

      Unlock serious performance and aggressive sound with the Comp Cams Thumpr Hydraulic Roller Cams—the perfect choice for muscle car enthusiasts and performance builders looking to make a statement. These cams are specifically designed to deliver increased horsepower and torque while providing that signature "thumpy" idle that turns heads at every stoplight.

      Whether you're building a street machine or upgrading your engine for track days, the Thumpr cam gives your vehicle a noticeable boost in performance without compromising reliability. These cams feature a hydraulic roller design that offers superior durability, allowing for better valve control at higher RPMs, reducing friction, and increasing engine efficiency.

      For those seeking an even more aggressive profile, the Mutha Thumpr cam offers an even more intense sound and performance upgrade. With optimized lobe profiles, this cam produces a lopey idle and delivers peak performance at mid to high RPM ranges, ensuring your engine performs at its best when you need it most.

      Perfect for anyone looking to enhance the power, sound, and style of their ride, the Thumper cam is engineered for vehicles with modified cylinder heads, high-compression ratios, and other performance upgrades. Comp Cams delivers exceptional quality and precision, ensuring that these cams will stand the test of time.

      Shop JEGS today to take your engine's performance and sound to the next level with Comp Cams Thumpr Hydraulic Roller Cams—designed for the enthusiast who wants more power and attitude.

    Part TypeCamshaft Kit
    Product LineComp Cams Thumpr Hydraulic Roller Cams
    BrandCOMP CAMS
    Package Height5.2
    Package Width10.4
    Package Length25.4
    Weight24.15 PG
    Part CategoryPerformance Parts
    Exh. Duration @ .050 In. (Deg)249
    Cam StyleHydraulic roller tappet
    Grind Number291THR7
    Exh. Duration Advertised (Deg)311
    Locks IncludedYes
    Engine Make/SizeChevy Small Block (262-400)
    Retainers IncludedYes
    Intake Valve Lift With Factory Rocker Arm Ratio (I0.521
    Int. Duration @ .050 In. (Deg)235
    Assembly Lubricant IncludedNo
    Basic Operating Rpm Range2,200-5,900
    Pushrods IncludedYes
    Gaskets IncludedNo
    Rocker Arms IncludedNo
    Intake Valve Lift0.521 in (13.233 mm)
    Computer-Controlled CompatibleNo
    Int. Duration Advertised (Deg)291
    Lobe Separation (Deg)107
    Rpm Range2200-5900
    Lifter StyleHydraulic roller
    Advertised Duration291 int./311 exh.
    Exhaust Valve Lift With Factory Rocker Arm Ratio (0.507
    Valve Springs IncludedYes
    UsageStreet/Performance
    Valve Lift With Factory Rocker Arm Ratio0.521 int./0.507 exh.
    QuantitySold as a kit
    Valve Stem Seals IncludedYes
    Exhaust Valve Lift0.507 in (12.878 mm)
    Advertised Intake Duration291
    Intake Duration At 050 Inch Lift235
    Exhaust Duration At 050 Inch Lift249
    Timing Chain StyleDouble roller
    Timing Chain And Gears IncludedYes
    Advertised Exhaust Duration311
    Lifter TypeHydraulic Roller Retrofit
    Part FitmentSemi Universal
    Duration At 050 Inch Lift235 int./249 exh.
    Valve Springs RequiredNo
    Lifters IncludedYes
    Vendor Part NumberK12-601-8
    Package Qty1
    Package TypeEA
    No Questions
    No Reviews

    Items You Need

    Universal Camshaft Installation/Removal Tool Includes 4 camshaft adapters

    JEGS

    Universal Camshaft Installation/Removal Tool Includes 4 camshaft adapters

    Part Number : 555-80599
    $4779$51.99
    You Save$4.20
    Precision Cam Degree Wheel Kit [11 in.]

    JEGS

    Precision Cam Degree Wheel Kit [11 in.]

    Part Number : 555-81621
    $14699$161.99
    You Save$15.00
    Valve Spring Compressor [Stud Mount]

    JEGS

    Valve Spring Compressor [Stud Mount]

    Part Number : 555-80521
    $5299$57.19
    You Save$4.20
    Valvetrain Checking Springs Light tension springs

    JEGS

    Valvetrain Checking Springs Light tension springs

    Part Number : 555-80523
    $839$8.99
    You Save$0.60
    Engine Assembly Lube [4 oz. Bottle]

    JEGS

    Engine Assembly Lube [4 oz. Bottle]

    Part Number : 555-28000
    $589$6.99
    You Save$1.10
    Valve Spring Compressor [Stud Mount]

    JEGS

    Valve Spring Compressor [Stud Mount]

    Part Number : 555-80518
    $919$9.99
    You Save$0.80
    Break-In/Engine Oil Supplement [12 oz. Bottle]

    JEGS

    Break-In/Engine Oil Supplement [12 oz. Bottle]

    Part Number : 555-28060
    $1009$11.99
    You Save$1.90
    Some parts are not legal for use in California or other states with similar laws / regulations
    p65 warning
    Your Cart

    Your shopping cart is empty!