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Big Mutha' Thumpr 243/257 Hydraulic Roller Cam for AMC 290-401

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UPC:
00036584266624
Availability:
This part ships direct from the manufacturer, lead times, stock and shipping may vary.
Weight:
10.75 LBS
$584.10

#SAVETHEFULLSIZEJEEP

A Portion Of The Proceeds From Your Purchase Supports The Development & Reproduction Of High Quality 1963-1991 Restoration Parts.

Big Mutha' Thumpr 243/257 Hydraulic Roller Cam for AMC 290-401

Big Mutha' Thumpr 243/257 Hydraulic Roller Cam for AMC 290-401

$584.10
Designed to deliver an aggressive, hard-hitting exhaust note at idle, the Thumpr camshaft series from COMP Cams also delivers excellent horsepower gains and a broad torque curve. A perfect choice for muscle cars and street rods, the Thumpr series' early intake valve opening and long exhaust duration create optimum overlap for that race car idle. The Thumpr grinds all require an aftermarket torque converter and lower gear ratio to ensure the drivetrain always puts the engine in its powerband. Additionally, Thumpr camshafts typically deliver reduced vacuum at idle, making a vacuum canister, pump or hydroboost a requirement for vehicles running power brakes.

Installation Instructions



This Part Fits:

YearMakeModelSubmodel
1974-1976JeepCherokeeBase
1977JeepCherokeeBase
1978JeepCherokeeBase
1979-1983JeepCherokeeBase
1981-1982JeepCherokeeChief
1983JeepCherokeePioneer
1974-1975JeepCherokeeS
1976JeepCherokeeS
1977JeepCherokeeS
1978-1980JeepCherokeeWide Track
1984-1991JeepGrand WagoneerBase
1984-1985JeepGrand WagoneerLimited
1971JeepJ-100Base
1972JeepJ-100Base
1973JeepJ-100Base
1970JeepJ-2500Base
1971-1972JeepJ-2500Base
1973JeepJ-2500Base
1970JeepJ-2600Base
1971-1972JeepJ-2600Base
1973JeepJ-2600Base
1970-1971JeepJ-3800Base
1971-1972JeepJ-4500Base
1973JeepJ-4500Base
1971-1973JeepJ-4600Base
1971-1973JeepJ-4700Base
1971JeepJ-4800Base
1972JeepJ-4800Base
1973JeepJ-4800Base
1974JeepJ10Base
1975JeepJ10Base
1976JeepJ10Base
1977-1988JeepJ10Base
1974JeepJ20Base
1975JeepJ20Base
1976-1988JeepJ20Base
1972-1975JeepWagoneerBase
1976JeepWagoneerBase
1977JeepWagoneerBase
1978JeepWagoneerBase
1979-1982JeepWagoneerBase
1982-1983JeepWagoneerBrougham
1973-1974JeepWagoneerCustom
1975JeepWagoneerCustom
1976JeepWagoneerCustom
1979-1983JeepWagoneerLimited


Advertised Exhaust Duration319
Advertised Intake Duration299
ApplicationsFits AMC 290, 304, 343, 360, 390 and 401
Assembly Lubricant IncludedNo
Basic Operating RPM Range2,500-6,400
C.A.R.B. E.O. NumberN/A
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.
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. Exemption ReasonN/A
California Proposition 65WARNING: Cancer and Reproductive Harm P65Warnings.ca.gov
Cam TypeHydraulic Roller
Camshaft Gear Attachment1-Bolt
Camshaft MaterialBillet Steel
Camshaft SeriesThumpr
DescriptionStreet/strip, needs 9.5:1 compression, 2800+ stall, intake, gears and headers, very rough idle.
Engine FamilyAmerican Motors 290-401 c.i. 8 Cylinder (1966-1991)
Exhaust Duration at .050 inch Lift257
Exhaust Valve Lift0.537
Grind Number299THR7
Intake Duration at .050 Inch Lift243
Intake Valve Lift0.552
Lifter TypeHydraulic Roller
Lifters IncludedNo
Lobe Separation107
UsageStreet/Performance
Valve Springs RequiredYes

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Parts returned that are not defective, are subject to a 25% restocking charge. JeepRecyclers.com/McDaniel Motor Co. is NOT responsible for any parts that have been altered, modified, disassembled, or damaged by misuse or an accident subsequent to the parts purchase.

Reconditioned parts come with a minimum warranty of 90 days, unless otherwise stated (Refer to product listing for warranty duration). The warranty is void if the parts are not returned in the same condition in which they are sold. Warranties for aftermarket parts are covered by the manufacturer.

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For orders delivered within the continental US where reason for return isn't a result of a JeepRecyclers.com/McDaniel Motor Co. error, the cost of the initial shipping charge and a return fee will be deducted from your refund. A prepaid shipping label(s) will be provided. The flat fee for each item being returned can be found in the chart below:

Retail cost of the item Per Item Return Fee
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From $25.00-$49.99 $5.75
From $50.00-$99.99 $7.75
More than $100.00 $9.75

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