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COMP Cams GK12-602-4 Big Mutha' Thumpr Hydraulic Flat Camshaft Kit for Chevy Small Block

(GMC G2500 1979-95, Yukon 1992-95, K1500 1979-86, 1988-95, C1500 1979-86, 1988-95, K2500 1979-86, 1988-95, Jimmy 1970-91 + 242 more models)

Manufacturer

Picture for manufacturer COMP Cams

Part Number

GK12-602-4
5 reviews
Sale Price

$628.95

Estimated ship date Friday, November 20

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Product Details

The COMP Cams Big Mutha' Thumpr GK12-602-4 is a complete hydraulic flat tappet camshaft kit engineered for Chevrolet small block V8 engines seeking aggressive idle characteristics and strong mid-range performance. This kit delivers the signature "thumper" sound with a loping idle that announces serious performance intent while maintaining street-friendly drivability.

Camshaft Specifications:

  • Advertised Duration: 243°/257° (Intake/Exhaust)
  • Duration at .050": 230°/244°
  • Valve Lift: .525"/.540" with 1.5 rocker ratio
  • Lobe Separation Angle: 107°
  • Hydraulic flat tappet design for reliable operation
  • Recommended RPM range: 1,600-5,800

Complete GK-Kit Includes:

  • Camshaft with advanced lobe profiles
  • Hydraulic lifters engineered for high-performance applications
  • Performance valve springs with dampers
  • Chrome moly retainers and locks
  • Camshaft installation assembly lubricant

This cam is ideal for street performance builds with 9.0:1-9.5:1 compression ratios and works exceptionally well with aftermarket intake manifolds, headers, and 2,000-2,800 RPM stall converters. The aggressive exhaust duration creates noticeable exhaust note and works best with exhaust systems featuring minimal restriction. Recommended for manual transmissions or automatic transmissions with higher stall converters due to the choppy idle characteristics.

Application: Chevrolet small block V8 engines including 262, 265, 267, 283, 302, 305, 307, 327, 350, and 400 cubic inch variants.

Products specifications

Fits

GMC G2500 1979-95, Yukon 1992-95, K1500 1979-86, 1988-95, C1500 1979-86, 1988-95, K2500 1979-86, 1988-95, Jimmy 1970-91, C3500 1979-86, 1988-95, K2500 Suburban 1979-86, 1992-95, K3500 1979-86, 1988-95 + 239 more models

Advertised Intake Duration

295

Basic Operating RPM Range

2,500-6,400

Cam Type

Hydraulic Flat Tappet

Exhaust Valve Lift

0.486

Intake Duration at .050 Inch Lift

243

Exhaust Duration at .050 inch Lift

257

Kit Type

GK-Kit - Cam and Gear Kit

K-Kit Upgrade

K12-602-4

AMAZON ASIN

B002EE77D8

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.

Gaskets Included

No

Locks Included

No

Lifters Included

Yes

Retainers Included

No

Timing Chain and Gears Included

Yes

Intake Valve Lift

0.5

Usage

Street/Strip

Advertised Exhaust Duration

313

Engine Family

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

Valve Stem Seals Included

No

Pushrods Included

No

Camshaft Series

Thumpr

quick and easy as well as best price

great experience, good price, item arrived within 4 days of purchase, would do business with again in future !

Great Products, Very Cheap, Fast Shipping. Will be a returning Customer. A+++

By far the lowest price i've seen on the web for what i have been trying to get, the Injen SRI for my juke. Great price fast shipping! Ill buy all my car stuff here from now on.

Reasonable price and shipping Wrong part!

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