Chevrolet Small Block Gen III LS1 345 (1997)
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Home » Racing Engines » Chevrolet Small Block Gen III LS1 345

Specifications

Chevrolet Small Block Gen III LS1 345ci (5.7 lt), 4 stroke
Introduced in 1997
5665cc
Click here

Dimensions

Cylinders arrangement: V8 (90o)
Strokes: 4
Bore x Stroke: 3.898 in (99.06 mm) x 3.62 in (91.9 mm)
Capacity: 5665 cc
Compression ratio:

Construction materials

A319 T5 (production) or A357-T6 aluminum alloy block with 234.7mm deck height and 111.8mm bore spacing
A356 T6 aluminium head
nodular iron crankshaft with 5 main bearings 65mm diameter
connecting rod length between centers 154.9mm, big end bearing diameter 53.3mm

Cylinder-head

crossflow design
OHV
camshaft in block with overhead valves (OHV), 2 valves/cyl - 16 valves total

Aspiration

╬Łatural with multipoint electronic Fuel Injection

Ignition

ECU
firing order 1-8-7-2-6-5-4-3, with Driver side 1 3 5 7, Passenger side 2 4 6 8
Animation

Cooling and lubrication

water cooled, Reverse flow water cooling
wet sump

Torque values

Models used and Output

Year Model Induction Compression ratio Power Torque
2001 Mosler MT900R MPFI 430 bhp / 321 KW
hrdp-9808-01-o%2Bthe-LS1-engine%2Bcutout.jpg Source

Service info (street engine)

Source
LS1/LS6 Engine Dimensions & Clearances

Production = (P), Service Limit = (SL), Out-of-Round = O-o-R
Run Out = RO, Inside Dia. = ID, Outside Dia. = OD

CAMSHAFT:
Base Circle Dia.:
'97-'04 LS1 = 19.7mm / 0.776"
'01 LS6 = 19.3mm / 0.760"
'02 -'04 LS6 = 19.0mm / 0.748
End Play: 0.025-0.305mm / 0.001-0.012"
Journal Dia.: 54.99-55.04mm / 2.164-2.166"
Journal Dia. O-o-R: 0.025mm / 0.001"
Intake Lobe Lift: 7.04mm / 0.277"
Exhaust Lobe Lift: 7.13mm / 0.281"
Poller Lifter Dia.: 17.78mm / 0.700"
RO @ Intermediate Journals: 0.05mm / 0.002"
Lobe Base Circle Radius:
'97-'04 LS1: 19.7mm / 0.776"
'01 LS6: 19.3mm / 0.760" (reduced for ^ valve lift)
'02-'04 LS6: 19.0mm / 0.748 " " " " " "

CONNECTING ROD:
Bearing Bore Dia.: 56.505-56.525mm / 2.224-2.225"
Bearing Bore O-o-R (P): 0.004mm / 0.00015"
Bearing Bore O-o-R (SL): 0.008mm / 0.0003"
Bearing Clearance (P): 0.015-0.063mm / 0.0006-0.00248"
Bearing Clearance (SL): 0.015-0.076mm/0.0006-0.003"
Bearing Width: 24mm / 0.9449"
Side Clearance: 0.11-0.51mm / 0.00433-0.02"
Center to Center: 154.89mm / 6.098"
Piston Pin Bore Dia.: 23.97mm / 0.9436"
Piston Pin Boss Width: 24mm / 0.9449"
Piston Pin Press Interference:0.020-0.043mm / 0.0008-0.0017"
Rod Bolts: M9 x 1" (replace with ARP/Katech if > 450HP)

CRANKSHAFT:
Rotation = Clockwise (looking at front of block)
Bearing Clearance (P): 0.018-0.054mm / 0.0007-0.00212"
Con Rod Journal Dia. (P): 53.318-53.338mm / 2.0991-2.0999"
Con Rod Journal Dia. (SL): 53.308mm Min. / 2.0987" Min.
Con Rod Journal Taper (P): 0.005mm / 0.0002"
(Maximum for 1/2 Journal length)
Con Rod Journal Taper (SL): 0.01mm Max. / 0.0004" Max.
Con Rod Journal O-o-R (P): 0.005mm / 0.0002"
Con Rod Journal O-o-R (SL): 0.01mm / 0.0004"
Con Rod Journal Width: 48.37mm / 1.902"
End Play: 0.04-0.2mm /0.0015-0.0078"
Main Journal Dia. (P): 64.993-65.007mm / 2.558-2.559"
Main Journal Dia. (SL): 64.993mm Min. / 2.558" Min.
Main Journal O-o-R (P): 0.003mm / 0.000118"
Main Journal O-o-R (SL): 0.008mm / 0.0003
Main Journal Taper (P): 0.01mm / 0.0004"
Main Journal Taper (SL): 0.02mm / 0.00078"
Main Journal Width: 22.99mm / 0.905"
Reluctor Ring RO: 0.25mm / 0.01"
(Measured @ 1.0mm/0.04" below tooth Dia.)
Crank RO : 0.05mm / 0.002" (Measured at rear flange)
Flywheel Bolt Base Circle: 78.99mm / 3.110"
Stroke: 92mm / 3.622"
Rear Seal ID: 114.99mm / 4.527"
Thrust Wall RO: 0.025mm / 0.001"
Thrust Wall Width (P): 26.14-26.22mm / 1.029-1.032"
Thrust Wall Width (SL): 26.32 Max. / 1.036" Max.

CYLINDER BORE:
Bore Dia.: 99.0-99.018mm / 3.897-3.898"
Bore Taper Thrust Side: 0.018mm Max. / 0.0007" Max.
Bank Angle = 45 degrees
Cylinder Bank Offset: 24.10mm / 0.949"

CYLINDER HEAD: A356 T6
Block Deck Flatness: 0.11mm / 0.004" (within a 6" area)
Block Deck Flatness: 0.22mm / 0.008" (length of head)
Exhaust Manifold Deck Flatness: 0.22mm / 0.008"
Intake Manifold Deck Flatness: 0.22mm / 0.008"
Height: 120.2mm / 4.732" (Deck to Rocker Cover Surfaces)
Valve Angle: 15 degrees
Valve Guide Material = Sintered Iron (Press IN)
Valve Guide Seperation: 48.6mm / 1.913"
Valve Seat Angles: 30/45/60 degree blend into chamber
Valve Stem Dia.: 8.001mm / 0.315"

ENGINE BLOCK: A319 T5 / 107#'s
Length: 519mm / 20.43"
Width: 460mm / 18.11"
Deck Height: 234.57-234.82mm / 9.235-9.245"
Cylinder Bank Angle = 45 degrees
Cylinder Bank Offset: 24.10mm / 0.949"
Center Main = Crank Thrust Wall #3
Indexing = Crank CenterLine
Camshaft Bearing Bore Dia.: 55.063-55.088mm / 2.168-2.169"
Block Deck Flatness: 0.11mm / 0.004" (measured within 6")
Block Deck Flatness: 0.22mm / 0.008" (length of Deck)
Main Bearing Bore Dia. (P): 69.871-69.889mm / 2.750-2.751"
Valve Lifter Bore Dia. (P):21.417-21.443 / 0.843-0.844"

FUEL INJECTION:
LS1 Static Flow Rate = 3.6 gal/sec.
Cranking Fuel pressure = 53 to 63 psi

IGNITION:
Coil Output = 60mJ
Sparkplug Wire length = 219mm
Sparkplug Type = AC 41-931 / Beru Silverstone S1K
Sparkplug gap = 1.5mm / 0.060"

INTAKE MANIFOLD;
Head Deck Flatness: 0.5mm / 0.02" @ gasket mating surface
LS1 MAF ID = 75mm
LS1 Throttle Body ID = 75mm
LS6 MAF ID = 80mm
LS6 Throttle Body ID = 80mm

OIL PAN & FRONT/REAR COVER Alignment:
Oil Pan to Rear of Block: 0.0-0.25mm / 0.0-0.01"
(@ Bellhousing Surface)
Front Cover: 0.0-0.5mm / 0.0-0.2" (@ Oil Pan Surface)
Rear Cover: 0.0-0.5mm / 0.0-0.2" (@ Oil Pan Surface)

OIL PUMP:
Dia: 89.99mm / 3.543"
Gear Thickness: 10.69mm / 0.421"
Pressure Relief Setting (Factory): 60 psig @ 5,000 RPM

PISTONS: Cast Eutectic Aluminum, +'03 have coated skirts
Weight = 434 grams
Piston OD: 98.964-98.982mm / 3.8962-3.8969"
Piston to Bore Clearance(P): 0.018-0.054mm/0.0007-0.00212"
Piston to Bore Clear. (SL): 0.018-0.054mm / 0.0007-0.00212"
(Maximum)
Piston Deck Height in Operation: 0.203mm / 0.008"
(Above Deck Surface)
Top Land Thickness: 34mm / 0.177"

PISTON PINS:
Pin to Piston Bore (P): 0.01-0.02mm / 0.0004-0.00078"
Pin to Piston Bore (SL): 0.01-0.02mm / 0.0004-0.00078" Max.
Pin Dia.: 23.997-24.0mm / 0.9447-0.9448"
Pin Fit in Con Rod: 0.02-0.043mm / 0.00078-0.00169"
(Interference)

PISTON RINGS:
Top Comp. Thickness: 1.500mm / 0.59"
Top Comp. Gap Clocking: None Required
Top Comp. End Gap (P): 0.23-0.38mm / 0.009-0.0149"
Top Comp. End Gap (SL): 0.23-0.38mm / 0.009-0.0149" Max.
Top Comp. Groove (P):0.04-0.085mm / 0.00157-0.003346"
Top Comp. Groove (SL):0.04-0.085mm/0.00157-0.003346"Max.
2nd Comp. Thickness: 1.500mm / 0.59"
Top Comp Gap Clocking: None Required
2nd Comp. End Gap (P): 0.44-0.64mm / 0.0173-0.0251"
2nd Comp. End gap (SL): 0.44-0.64mm / 0.0173-0.0251" Max.
2nd Comp. Groove (P): 0.04-0.08mm / 0.00157-0.003149"
2nd Comp. Groove (SL):0.04-0.08mm/0.00157-0.003149"Max.
Oil Cont. Rail Thickness (2): 3.00mm / .188" (EACH)
Oil Cont. Top Rail Gap Clocking: 25 degrees from Top Ring
Oil Cont. 2nd Rail gap Clocking: 25 degrees from Expander
Oil Cont. End Gap (P): 0.18-0.69mm / 0.007-0.0271"
Oil Cont. End Gap (SL): 0.18-0.69mm / 0.007-0.0271" Max.
Oil Cont. Groove (P): 0.01-0.22mm / 0.0004-0.00866"
Oil Cont. Groove (SL):0.01-0.22mm / 0.0004-0.00866" Max.

VALVETRAIN:Hydraulic Roller
Rocker Arm Ratio = 1.70:1
Valve Lash Net Lash: No Adjustment
Valve Face Angle = 45 degrees
Valve Seat Angle = 46 degrees
Valve Seat RO: 0.05mm / 0.002" Max.
Valve Seat Width (Intake) = 1.02mm / 0.04"
Valve Seat Width (Exhaust) = 1.78mm / 0.07"
Valve Stem:
Clearances:
Intake (P): 0.025-0.066mm / 0.001-0.0026"
Intake (SL): 0.093mm / 0.0037" Max.
Exhaust (P): 0.025-0.066mm / 0.001-0.0026"
Exhaust (SL): 0.093mm / 0.0037" Max
Oil Seal Installed Height = 18.1-19.1mm / 0.712-0.752"
(Measured from VS Shim toTop Edge od Seal Body)
Valve Stem Dia. (P): 7.955-7.976mm / 0.313-0.314"
Valve Stem Dia. (SL) 7.9mm / 0.311 Min.
Valve Spring:
Free Length = 52.9mm / 2.08"
Pressure (Closed) = 340 N @ 45.75mm / 76# @ 1.80"
Pressure (Open) = 980 N @ 33.55mm / 220# @ 1.32"
Installed Height (Intake) = 45.75mm / 1.800"
Installed Height (Exhaust) = 45.75mm / 1.8"
Valve Guide Installed Height = 17.32mm / 0.682"
(Measured from Spring Seat Surface to Top of valve Guide)
Roller Lifter Dia.:17.78mm / 0.700"
Valve Material: Stainless Steel, Hollow Stems, Na filled Exhaust

Cams
1997-2000
0.472/0.479, 202/210 on 117

2001 LS1
.500/0.500, 198/208 on 115.5LSA

2001 LS6
0.525/0.525, 204/211 on 116

2002 LS6
0.551/0.547, 204/218 on 117.5

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