AFR® - Eliminator 23° LT1 Street Cylinder Heads

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1978 GMC CK Pickup
Fits Following Model(s):
  • With Small Block Chevy Engine
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    Product Details

    GMC CK Pickup With Small Block Chevy Engine 1978, Eliminator 23° LT1 Street Cylinder Heads by AFR®. AFR's LT1/LT4 SBC heads are designed for the Gen II reverse cooled SBC engine from 1992-1997. They feature all the same benefits and quality components as AFR's Gen I SBC heads in addition to dual pattern valve cover mounting holes and Titanium Retainers as standard equipment. Not compatible with self-aligning rocker arms.This premium product is the best way to go for those looking for the highest quality replacement that offers supreme levels of quality, performance and reliability. Designed to provide a perfect fit for a hassle free installation, this reliable product can help you get you vehicle back on the road faster and easier.


    Accessory Bolt Holes Drilled: Yes
    Angle Mill: 0.009" per cc 55cc Maximum
    Carb EO#: D-250-2
    CNC-Machined Combustion Chamber: Yes
    CNC-Machined Exhaust Runner: Yes
    CNC-Machined Intake Runner: Yes
    Combustion Chamber Style: Heart
    Combustion Chamber Volume: 55 cc
    Cylinder Head Finish: Natural
    Cylinder Head Material: Aluminum
    Cylinder Head Style: Assembled
    Deck Thickness: .750"
    Exhaust Port Dimension: 1.450" H x 1.550" W
    Exhaust Port Location: .100" Raised
    Exhaust Port Shape: Square
    Exhaust Runner Volume: 64cc
    Exhaust Valve Angle: 23
    Exhaust Valve Diameter: 1.6"
    Flat Mill: 0.006" per cc 60cc Maximum
    Guideplate Pushrod Size: 5/16"
    Heat Crossover: Yes
    Intake Port Dimension: 2.110" H x 1.265" W x 5/16" Radius
    Intake Port Location: Stock
    Intake Port Shape: Rectangular
    Intake Runner Volume: 195cc
    Intake Valve Angle: 23°
    Intake Valve Diameter: 2.050"
    Lock Style: 7 degree
    Machined for O-Ring: No
    Material: A356 Aluminum
    Max Valve Spring Pocket Machining: 1.750" OD
    Maximum Valve Lift: 0.6"
    Minimum Bore Diameter: 4"
    Minimum Cross Sectional Area: 1.905 sq. in.
    Number of Springs Per Valve: Dual
    Oiling Style: Through pushrod
    Outside Diameter of Outer Spring: 1.290"
    Quantity: 1 Pair.
    Retainer Material: Titanium
    Rocker Arm Nut Thread Size: 3/8-24"
    Spark Plug Dimensions: 14 mm x .750" with Gasket Seat
    Spark Plug Style: Angle
    Steam Holes Drilled: No
    Valve Angle: 23°
    Valve Cover Bolt Pattern: Perimeter Bolt
    Valve Cover Mounting Style: Center and perimeter bolt
    Valve Guide Material: Bronze
    Valve Seat Machine Style: 3-angle
    Valve Seat Material: Ductile iron
    Valve Seats Machined: Yes
    Valve Spring Pocket Diameter: 1.460"


    • 100% CNC Ported Combustion Chambers
    • 100% CNC Ported Exhaust Ports
    • 100% CNC Ported Intake Ports
    • Competition 5-angle Valve Job
    • Designed to meet the needs of racers or street enthusiasts
    • Made using the latest in modern technology and advanced processes
    • Strict quality control and thorough testing


    • 8mm Bead Lock Intake Valve, 2.050" x 4.900" Overall Valve Length
    • 8mm Bead Lock Exhaust Valve, 1.600" x 4.950" Overall Valve Length
    • PAC Racing Spring 1.290" OD Hydraulic Roller Dual Valve Spring, 140 lbs on seat, 0.600" maximum lift, Max RPM 6300-6500(upgrades available)
    • 7° Titanium Retainer 1.245 OD x 0.885 ID x 0.655 ID
    • 7° Bead Lock Valve Keepers
    • ARP 3/8" Rocker Studs
    • Adjustable 5/16" Guide Plates
    • Viton Valve Seals 0.600" O.D x 0.495" I.D
    • Hardened Valve Spring O.D Locator 1.380" O.D x 0.570" I.D
    • Ductile Iron Intake Valve Seats 2.200" O.D x 1.750" I.D x 0.375" Deep
    • Ductile Iron Exhaust Valve Seats 1.696" O.D x 1.325" I.D x 0.305" Deep
    • 8 mm Bronze Valve Guides 0.502" O.D x 2.100" O.A.L: AFR #9051

    For over 45 years, Air Flow Research (AFR) has been defining technological leadership in cylinder head manufacturing and flow dynamics. This complete commitment to performance has enabled AFR® cylinder heads to find themselves on the fastest race cars and the most powerful street machines in the country. Air Flow Research’s design, engineering, and manufacturing technology never rests. As a leader today, AFR is investing in the horsepower of tomorrow with new manufacturing technology, complex dyno testing, and proprietary flow testing methods. And to assure a long-standing tradition to performance, AFR is bringing up a new generation of racers and engineers to meet the demands of tomorrow’s engine builders.

    California Residents

    WARNING Cancer and Reproductive Harm.

    Part Number:


    Aluminum Cylinder Head & Manifold Warranty

    Effective on purchase made on or after January 1, 2010, AFR warranties AFR aluminum cylinder head castings for the lifetime of the product with proof of purchase to the original purchaser. Additionally, valves, guides, valve seats, valve springs, retainers, locks, studs, guide plates, and valve seals are warranted for two years to the original purchaser with proof of purchase. All returns must have a RMA number in order to be returned, call for a RMA number. Parts must be returned prepaid freight by the original purchaser. This warranty doesn’t cover fitness for purpose and/or merchantability on any product sold by AFR. Non-AFR castings are covered by the manufacturer of that casting.

    Composite Manifold Warranty:

    AFR warranties their composite intake manifold to be free of defects for a period of one year's time.

    This warranty does not cover the following:

    1. Failure due to improper installation or maintenance, abuse, misuse, unauthorized repairs, modifications, or alterations determined at the sole discretion of AFR. If your machine shop, engine builder or installer performs any unauthorized repairs, AFR warranty is voided and AFR will not reimburse any cost you incurred.
    2. Removal or replacement cost.
    3. Costs incurred due to down time of the vehicle.
    4. Damage to related components.
    5. Marine salt water corrosion.
    6. Corrosion from not using/refreshing antifreeze.
    7. Fitness for purpose or merchantability.
    Magnuson-Moss Warranty Act:
    Legally, a vehicle manufacturer cannot void the warranty on a vehicle due to an aftermarket part unless they can prove that the aftermarket part caused or contributed to the failure in the vehicle (per the Magnuson Moss Warranty Act (15 U.S.C. 2302(C)) Learn More
    Low Prices Price match guarantee
    Guaranteed Fitment Always the correct part
    In-House Experts We know our products
    Easy Returns Quick & Hassle Free

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