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#35020174

ATK HP98 Chevy 350 Base Engine 345HP

Block: New GM LT1/LT4
Bore/Stroke: 4.065” x 3.622”
Displacement (cu.in): 376 CID

Level Of Dress:

#1 Base Engine

$3,709.00

/each

Factory Shipped

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Product Summary

Long Block Crate Engine Type, 9.1:1 Compression Ratio

Block: New GM LT1/LT4
Bore/Stroke: 4.065” x 3.622”
Displacement (cu.in): 376 CID
Crankshaft: Manley 4340 forged 58 tooth reluctor wheel
Rods: Manley 4340 forged H beam 6.125” ARP 2000 bolts

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Key Specs

Crate Engine Type	Long Block
Engine Displacement	5.7 liters
Compression Ratio	9.1:1
Camshaft Type	Hydraulic Roller
Cylinder Head Material	Cast Iron

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Need To Know

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ATK Engines HP98 Details

Engine Specifications:

HP: 345

TQ: 400

Block: OE block 4 bolt main 1pc seal 1987-2000

Bore/Stroke: 4.040 x 3.480

Displacement: 350

Crankshaft: OE Reground external balance rear of crank/internal balance front of the crank

Rods: OE powder metal 5.7”

Pistons: Hypereutectic 9.1:1 compression

Rings: Moly

Camshaft: Hyd. roller

Cam Specs: 220/224 @50 .495in/.502ex 110LSA

Timing Chain: Double roller

Cylinder Heads: ATK cast iron 76cc/165cc 1.94/1.50

Rocker Arms: Stamped steel 1.5 ratio

Oil Pan: Rear sump 5qt (not for Chevelles with steering behind crossmember, some corvettes and 62-67 chevy II’s)

Oil Pump: Melling high volume

Recommended Components:

Balancer: PowerBond internal balance 8” #PB1046-N

Flexplate/Flywheel: Pioneer #FRA-159 external balance 168 tooth

Intake Manifold: Weiand stealth dual plane #8150

Distributor: HEI (Iron gear)

Water Pump: OE long pump

Carburetor: Quick Fuel 680CFM vacuum secondary’s with electric choke #HR-680

Fuel Pump: Holley mechanical 110GPH #12-327-11

Spark Plugs: Champion #RV12C

Spark Plug Wires: 8mm

Engine Info:

Oil: Conventional / Non synthetic 10W30 with Comp Cam zinc additive #159 for first 3000 miles

Oil Filter: Wix or K and N per application

Timing: 34-36 Degrees

Spark Plug Gap: .035”

Firing Order: 18436572

Octane: 91+

Stall Converter: 2200-2500

Exhaust: 1 5/8+ Headers

Disclaimer: The parts listed are ATK’s recommendations of parts to be used to obtain our power figures listed. Power figures can vary based on parts used by the end user. It is the customer’s responsibility to verify components will work in their application. Some modifications to the vehicle may be required using these and or other aftermarket parts. . ATK reserves the right to substitute parts used in engines if necessary.

Guides & Documents

Warranty (ATK Engines)

Technical Information (ATK Engines)

CARB Warning

Follow EPA, CARB, and state regulations for engine changes

Emissions warning: this part is for vehicle engine changes, not direct oem engine replacements. In California, engine changes are legal when done in compliance with California bureau of automotive repairs (bar) engine change policy. For assistance, call bar referee at: (800) 622-7733. And see https://bar.Ca.Gov/consumer/smog_check_program/engine_changes. All customers must comply with federal epa mobile source enforcement memorandum no. 1a (and addendum) and all applicable state regulations when conducting engine changes. Improper installation and/or use of this part in California may subject the installer and/or owner to a $37,500 penalty per violation per vehicle, revocation of registration, loss of use on California public right of ways, and proof of correction for tampering. There are similar restrictions and penalties under federal law and laws of all states for use of this engine change part on makes or models of vehicles that render them noncompliant with applicable state and/or federal emission laws with penalties under federal law of up to approximately $45,268 per tampered vehicle and/or engine

CA Prop 65

CARB warning

ATK Engines HP98 Specifications

KEY SPECS
MFG. Part #	HP98
Brand	ATK Engines
Crate Engine Type	Long Block
Engine Displacement	5.7 liters
Compression Ratio	9.1:1
Camshaft Type	Hydraulic Roller
Cylinder Head Material	Cast Iron
Camshaft Duration (.050 in)	220° intake / 224 ° exhaust
Camshaft Lift (in)	.528 intake / .536 exhaust
Bore x Stroke (in)	4.040" x 3.480"
Carburetor Included	No
Intake Manifold Included	No
Distributor Included	No
Valve Covers Included	Yes
Engine Balance	Internal/External
Cylinder Heads Included	Yes
Rear Main Seal Style	1-piece
Throttle Body Included	No
Oil Pan Included	Yes
Timing Cover Included	Yes
Water Pump Included	No
Harmonic Balancer Included	No
Flexplate Included	No
Flywheel Included	No
Air Cleaner Included	No
Spark Plugs Included	No
Spark Plug Wires Included	No
Computer Included	No
Wiring Harness Included	No

GENERAL
Assembled	Yes
Material Type	Cast Iron
Sold in Quantity	Each
Crate Engine Family	Chevy Small Block
Supercharger Included	No

Ratings & Reviews

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Fitment

1991-1993 Buick Roadmaster

Gen 1 L03 Small Block Chevy

1994 Buick Roadmaster

Gen 1 L05 Small Block Chevy

1995-1996 Buick Roadmaster

Gen 2 LT1 Small Block Chevy

1991-1992 Cadillac Brougham

1-Piece Rear Main 305 LB9

1999-2000 Cadillac Escalade

Vortec L31 Small Block Chevy

1990-1992 Cadillac Fleetwood

Gen 1 L05 Small Block Chevy

1993-1996 Cadillac Fleetwood

Gen 2 LT1 Small Block Chevy

1987 Chevy Blazer

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1988-1994 Chevy Blazer

Gen 1 L05 Small Block Chevy

1986 Chevy C10

1-Piece Rear Main 305 LG4
Gen 1 L05 Small Block Chevy

1986 Chevy C10 Suburban

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1988 Chevy C15

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1988-1995 Chevy C1500

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1996 Chevy C1500

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy
Vortec L30 Small Block Chevy
Vortec L31 Small Block Chevy

1997-1999 Chevy C1500

Gen 1 L05 Small Block Chevy
Vortec L30 Small Block Chevy
Vortec L31 Small Block Chevy

1992-1995 Chevy C1500 Suburban

Gen 1 L05 Small Block Chevy

1996-1999 Chevy C1500 Suburban

Gen 1 L05 Small Block Chevy
Vortec L31 Small Block Chevy

1986-1987 Chevy C20

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1986 Chevy C20 Suburban

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1988-1995 Chevy C2500

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1996 Chevy C2500

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy
Vortec L30 Small Block Chevy
Vortec L31 Small Block Chevy

1997-1998 Chevy C2500

Gen 1 L05 Small Block Chevy
Vortec L30 Small Block Chevy
Vortec L31 Small Block Chevy

1999 Chevy C2500

Gen 1 L05 Small Block Chevy
Vortec L31 Small Block Chevy

1992-1995 Chevy C2500 Suburban

Gen 1 L05 Small Block Chevy

1996-1999 Chevy C2500 Suburban

Gen 1 L05 Small Block Chevy
Vortec L31 Small Block Chevy

1986 Chevy C30

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1988-1995 Chevy C35

Gen 1 L05 Small Block Chevy

1996-1999 Chevy C35

Gen 1 L05 Small Block Chevy
Vortec L31 Small Block Chevy

1988-1995 Chevy C3500

Gen 1 L05 Small Block Chevy

1996-1999 Chevy C3500

Gen 1 L05 Small Block Chevy
Vortec L31 Small Block Chevy

1986 Chevy Camaro

1-Piece Rear Main 305 LB9

1987-1991 Chevy Camaro

1-Piece Rear Main 305 LB9
Gen 1 L98 Small Block Chevy

1992 Chevy Camaro

1-Piece Rear Main 305 LB9
Gen 1 L98 Small Block Chevy
Gen 2 LT1 Small Block Chevy

1993-1995 Chevy Camaro

Gen 2 LT1 Small Block Chevy

1996-1999 Chevy Camaro

Gen 2 LT1 Small Block Chevy
Vortec L31 Small Block Chevy

1986-1993 Chevy Caprice

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1994-1995 Chevy Caprice

Gen 2 LT1 Small Block Chevy

1996 Chevy Caprice

Gen 2 LT1 Small Block Chevy
Vortec L31 Small Block Chevy

1986-1991 Chevy Corvette

Gen 1 L98 Small Block Chevy

1992-1995 Chevy Corvette

Gen 2 LT1 Small Block Chevy

1996 Chevy Corvette

Gen 2 LT1 Small Block Chevy
Vortec L31 Small Block Chevy

1986-1987 Chevy El Camino

Gen 1 L03 Small Block Chevy

1996-1999 Chevy Express 1500

Gen 1 L05 Small Block Chevy
Vortec L30 Small Block Chevy
Vortec L31 Small Block Chevy

2000-2002 Chevy Express 1500

Vortec L30 Small Block Chevy

1996 Chevy Express 2500

Gen 1 L05 Small Block Chevy
Vortec L30 Small Block Chevy
Vortec L31 Small Block Chevy

1997 Chevy Express 2500

Gen 2 LT1 Small Block Chevy
Vortec L30 Small Block Chevy
Vortec L31 Small Block Chevy

1998-1999 Chevy Express 2500

Gen 1 L05 Small Block Chevy
Vortec L30 Small Block Chevy
Vortec L31 Small Block Chevy

2000-2002 Chevy Express 2500

Vortec L30 Small Block Chevy

1996-1999 Chevy Express 3500

Gen 1 L05 Small Block Chevy
Vortec L31 Small Block Chevy

1986-1993 Chevy G10

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1994-1995 Chevy G10

Gen 1 L03 Small Block Chevy

1986-1995 Chevy G20

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1986-1995 Chevy G30

Gen 1 L05 Small Block Chevy

1996 Chevy G30

Gen 1 L05 Small Block Chevy
Vortec L31 Small Block Chevy

1994-1995 Chevy Impala

Gen 2 LT1 Small Block Chevy

1996 Chevy Impala

Gen 2 LT1 Small Block Chevy
Vortec L31 Small Block Chevy

1986 Chevy K10

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1986 Chevy K10 Suburban

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1988-1995 Chevy K1500

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1996-1999 Chevy K1500

Gen 1 L05 Small Block Chevy
Vortec L30 Small Block Chevy
Vortec L31 Small Block Chevy

1992-1995 Chevy K1500 Suburban

Gen 1 L05 Small Block Chevy

1996-1999 Chevy K1500 Suburban

Gen 1 L05 Small Block Chevy
Vortec L31 Small Block Chevy

1986 Chevy K20

Gen 1 L05 Small Block Chevy

1986 Chevy K20 Suburban

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1988-1995 Chevy K2500

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1996 Chevy K2500

Gen 1 L05 Small Block Chevy
Vortec L31 Small Block Chevy

1997-1998 Chevy K2500

Gen 1 L05 Small Block Chevy
Vortec L30 Small Block Chevy
Vortec L31 Small Block Chevy

1999 Chevy K2500

Gen 1 L05 Small Block Chevy
Vortec L31 Small Block Chevy

1992-1995 Chevy K2500 Suburban

Gen 1 L05 Small Block Chevy

1996-1999 Chevy K2500 Suburban

Gen 1 L05 Small Block Chevy
Vortec L31 Small Block Chevy

1986 Chevy K30

Gen 1 L05 Small Block Chevy

1988-1995 Chevy K3500

Gen 1 L05 Small Block Chevy

1996-1999 Chevy K3500

Gen 1 L05 Small Block Chevy
Vortec L31 Small Block Chevy

1986 Chevy K5 Blazer

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1986-1988 Chevy Monte Carlo

Gen 1 L03 Small Block Chevy

1986-1995 Chevy P30

Gen 1 L05 Small Block Chevy

1996-1999 Chevy P30

Gen 1 L05 Small Block Chevy
Vortec L31 Small Block Chevy

1987 Chevy R10

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1987 Chevy R10 Suburban

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1988 Chevy R10 Suburban

Gen 1 L05 Small Block Chevy

1989-1991 Chevy R1500 Suburban

Gen 1 L05 Small Block Chevy

1987 Chevy R20

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1988 Chevy R20

Gen 1 L05 Small Block Chevy

1987-1988 Chevy R20 Suburban

Gen 1 L05 Small Block Chevy

1995 Chevy R25

Gen 1 L05 Small Block Chevy

1996-1999 Chevy R25

Gen 1 L05 Small Block Chevy
Vortec L31 Small Block Chevy

1989 Chevy R2500

Gen 1 L05 Small Block Chevy

1989-1991 Chevy R2500 Suburban

Gen 1 L05 Small Block Chevy

1987-1988 Chevy R30

Gen 1 L05 Small Block Chevy

1989-1991 Chevy R3500

Gen 1 L05 Small Block Chevy

1995 Chevy Silverado

Gen 1 L05 Small Block Chevy

1996-1999 Chevy Silverado

Gen 1 L05 Small Block Chevy
Vortec L31 Small Block Chevy

1987-1994 Chevy Suburban

Gen 1 L05 Small Block Chevy

1995 Chevy Suburban 1500

Gen 1 L05 Small Block Chevy

1996-1999 Chevy Suburban 1500

Gen 1 L05 Small Block Chevy
Vortec L31 Small Block Chevy

1995 Chevy Tahoe

Gen 1 L05 Small Block Chevy

1996-1999 Chevy Tahoe

Gen 1 L05 Small Block Chevy
Vortec L31 Small Block Chevy

1987 Chevy V10

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy

1987-1988 Chevy V10 Suburban

Gen 1 L05 Small Block Chevy

1989-1991 Chevy V1500 Suburban

Gen 1 L05 Small Block Chevy

1987 Chevy V20

Gen 1 L05 Small Block Chevy

1987-1988 Chevy V20 Suburban

Gen 1 L05 Small Block Chevy

1989-1991 Chevy V2500 Suburban

Gen 1 L05 Small Block Chevy

1987-1988 Chevy V30

Gen 1 L05 Small Block Chevy

1989-1991 Chevy V3500

Gen 1 L05 Small Block Chevy

1998-1999 GMC C1500

Vortec L31 Small Block Chevy

1992-1999 GMC C1500 Suburban

Vortec L31 Small Block Chevy

1987-1995 GMC G1500

Gen 1 L05 Small Block Chevy

1987-1995 GMC G2500

Gen 1 L05 Small Block Chevy

1987-1994 GMC G3500

Gen 1 L05 Small Block Chevy

1995-1996 GMC G3500

Gen 1 L05 Small Block Chevy
Gen 1 L98 Small Block Chevy

1986 GMC Jimmy

Gen 1 L05 Small Block Chevy

1987 GMC Jimmy

Gen 1 L03 Small Block Chevy
Gen 1 L05 Small Block Chevy
Gen 1 L98 Small Block Chevy

1988-1990 GMC Jimmy

Gen 1 L05 Small Block Chevy

1998-1999 GMC K1500

Vortec L31 Small Block Chevy

1981-1986 GMC K1500 Suburban

Gen 1 L05 Small Block Chevy
Gen 1 L98 Small Block Chevy

1992-1999 GMC K1500 Suburban

Vortec L31 Small Block Chevy

1986 GMC K2500

Gen 1 L05 Small Block Chevy

1996-2000 GMC K2500

Vortec L31 Small Block Chevy

1992-1993 GMC K2500 Suburban

Gen 1 L05 Small Block Chevy

1987 GMC R1500 Suburban

Vortec L31 Small Block Chevy

1988-1991 GMC R1500 Suburban

Gen 1 L98 Small Block Chevy

1996-2000 GMC Savana 1500

Vortec L31 Small Block Chevy

1987-1991 GMC V1500 Suburban

Gen 1 L05 Small Block Chevy
Gen 1 L98 Small Block Chevy

1987 GMC V2500

Gen 1 L05 Small Block Chevy
Gen 1 L98 Small Block Chevy

1987-1991 GMC V2500 Suburban

Gen 1 L05 Small Block Chevy
Gen 1 L98 Small Block Chevy

1992-2011 GMC Yukon

Vortec L31 Small Block Chevy