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COMP Cams GK12-601-4 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

GK12-601-4
9 reviews
Sale Price

$628.95

Estimated ship date Friday, November 20

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Product Details

The COMP Cams GK12-601-4 Mutha' Thumpr camshaft kit delivers an aggressive idle with excellent throttle response for Chevrolet small block engines. This complete GK-Kit (Go-Kit) includes everything needed for a camshaft upgrade, featuring a hydraulic flat tappet camshaft with 235/249 degrees of advertised duration.

Key Specifications:

  • Advertised Duration: 235° Intake / 249° Exhaust
  • Duration at .050": 207° Intake / 221° Exhaust
  • Valve Lift: .480" Intake / .488" Exhaust (with 1.5 rocker ratio)
  • Lobe Separation Angle: 107°
  • Hydraulic flat tappet design

Kit Includes:

  • Mutha' Thumpr camshaft
  • Hydraulic lifters
  • Valve springs and retainers
  • Spring seats and locks
  • Assembly lubricant
  • Timing set components

This camshaft produces the signature Thumpr sound with a lopey idle (approximately 1,000-1,500 RPM) while maintaining good drivability and vacuum for power brakes. Ideal for street machines, hot rods, and muscle cars seeking that classic aggressive cam sound. Designed for engines with 9.0:1 to 10.5:1 compression ratio and requires 2,000+ RPM stall converter and 3.55+ rear gears for optimal performance.

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 Exhaust Duration

305

Basic Operating RPM Range

2,200-6,100

Cam Type

Hydraulic Flat Tappet

Exhaust Valve Lift

0.476

Intake Valve Lift

0.489

Exhaust Duration at .050 inch Lift

249

Kit Type

GK-Kit - Cam and Gear Kit

K-Kit Upgrade

K12-601-4

AMAZON ASIN

B002EE365Q

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

Intake Duration at .050 Inch Lift

235

Lifters Included

Yes

Retainers Included

No

Timing Chain and Gears Included

Yes

Usage

Street/Strip

Advertised Intake Duration

287

Engine Family

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

Valve Stem Seals Included

No

Pushrods Included

No

Camshaft Series

Thumpr

First of all, I can not believe how fast I recieved my order, 2 DAYS! Best of all, the instructions made it easy for a non mechanic like me to install.

The ordering process was very simple and the prices could not be beat. The processing time to ship the order was a little longer than usual, but for the price savings, it was well worth it!

Damn fast on the shipping and great price on the item a great place to shop

Ordered a CAI kit and Autoplicity had the lowest price. They're website didn't correctly match my vehicle to the product and it took a few days to ship. They're support was friendly and quick when I emailed them about the delay.

Great customer service, item shipped quickly. Very satisfied.

simple and user friendly

Great site. Provided needed technical specs. Shipped promptly. Although I had to ask for the tacking number, it was not emailed, one was provided promptly upon request.

I couldn't find these ARP studs anywhere else for this price! $20 less than ANYWHERE! Definitely coming back to shop at Autoplicity.

This is the easiest purchase I ever made. The visor is great and installation was a breeze. The service by Autoplicity was A-1. Shipping was better than standard. Will buy from them again.

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