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COMP Cams 12-601-20 Mutha Thumpr 235/249 Hydraulic Flat Camshaft for Chevy Small Block

(GMC G2500 1979-95, Yukon 1992-95, K1500 1979-99, C1500 1979-99, K2500 1979-95, 1998, Jimmy 1970-91, Savana 2500 1996-2002 + 259 more models)

Manufacturer

Picture for manufacturer COMP Cams

Part Number

12-601-20
7 reviews
Sale Price

$468.95

Estimated ship date Sunday, November 22

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Product Details

The COMP Cams Mutha' Thumpr camshaft is engineered to deliver an aggressive, race-inspired exhaust note at idle while providing substantial horsepower gains and a broad torque curve. This hydraulic flat tappet camshaft features 235° intake and 249° exhaust duration, creating the signature Thumpr sound that defines muscle car performance.

Key Features:

  • Hydraulic flat tappet design for Chevrolet Small Block engines
  • Early intake valve opening and extended exhaust duration create maximum overlap for aggressive idle characteristics
  • Broad torque curve delivers excellent street performance and throttle response
  • Ideal for muscle cars, street rods, and high-performance street applications
  • Premium lobe profiles optimized for power delivery across the RPM range

Important Installation Requirements:

  • Aftermarket torque converter required for automatic transmissions
  • Lower gear ratio (3.73 or numerically higher) recommended to keep engine in optimal powerband
  • Reduced idle vacuum requires vacuum canister, electric vacuum pump, or hydroboost system for power brake applications
  • Professional installation and proper valve train components strongly recommended

This camshaft delivers the perfect combination of aggressive sound and real-world performance for enthusiasts who want that unmistakable race car idle with proven street reliability.

Products specifications

Fits

GMC G2500 1979-95, Yukon 1992-95, K1500 1979-99, C1500 1979-99, K2500 1979-95, 1998, Jimmy 1970-91, Savana 2500 1996-2002, Savana 1500 1996-2002, C3500 1979-95, K2500 Suburban 1979-95, K3500 1979-95 + 255 more models

Advertised Exhaust Duration

305

Basic Operating RPM Range

2,200-6,100

Grind Number

287TH7

Cam Type

Hydraulic Flat Tappet

Exhaust Valve Lift

0.476

Intake Valve Lift

0.489

Exhaust Duration at .050 inch Lift

249

Camshaft Material

Nitrided Cast Iron

Assembly Lubricant Included

Yes

Lifters Included

No

Valve Springs Required

Yes

Lifter Type

Hydraulic Flat Tappet

Prop 65

WARNING: Cancer and Reproductive Harm P65Warnings.ca.gov

C.A.R.B. Exempt for Foreign Vehicles Manufactured Before 1967?

Yes, but must meet tailpipe emission standards for year of vehicle.

C.A.R.B. Exempt for On-Road Vehicles?

No

C.A.R.B. Exempt for Racing and Off-Road Only Vehicles?

Yes, but must be a race/competition only vehicle.

C.A.R.B. Exempt for California Certified Vehicles Manufactured Before 1965?

Yes, but must meet tailpipe emission standards for year of vehicle.

C.A.R.B. Exempt for Federally Certified Vehicles Manufactured Before 1967?

Yes, but must meet tailpipe emission standards for year of vehicle.

Camshaft Gear Attachment

3-Bolt

Intake Duration at .050 Inch Lift

235

LOBE SEPARATION

107

Usage

Street/Strip

AMAZON ASIN

B002EDX6R0

Advertised Intake Duration

287

Engine Family

Chevrolet 262-400 c.i. 8 Cylinder (1958-1998)

Camshaft Series

Thumpr

Fast! Fast, fast, Fast! Fast, fastFast! Fast, fast

Ordered a Flex-a-lite 420 dual shrouded fan on Wednesday night and had it in my hands saturday afternoon! Great price and prompt shipping.

Overall quick shipping and nothing was missing or broken!<br>A little tricky install but fast with some help.<br>I like the fact that they have competitive pricing and there site is nice and secure.

Autoplicity had the best price on the part I needed and was in stock. Easy ordering process and good correspondence.

Great.

fast shipping and great prices

Received my product today was happy with the item purchased and will buy again from Autoplicity. Was received in a timely manner and like described

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