Configuration 90 OHV V-8 with cast-iron or aluminum blocks and heads
Cylinders (Front to Back) Drivers side: 1-3-5-7 - Passenger side: 2-4-6-8
Firing Order Clockwise on distributor: 1-8-4-3-6-5-7-2 (Gen. I, II and Vortec) - 1-8-7-2-6-5-4-3 (Gen. III with eight coils) Computer controlled, no distributor.
Crankshaft Gen. I, II and Vortec: Forged or cast, five main bearings, thrust on rear bearing. Gen III: Cast, live main bearing, thrust on #3 center main bearings.
Crankshaft Journal Dia. 1955 - 1968: Small Journal: Mains 2.30" - Rods 2.00" | 1967 - 1996: Med Journal: Mains 2.45" - Rods 2.10" | 1970 - 1980: 400 Crank: Mains 2.65" - Rods 2.10" | 1997 - Up: Gen. III: Mains 2.558" - Rods 2.10"
Crank strokes Small Journal: 3.0" and 3.25" | Medium Journal: 3.0" - 3.10" - 3.25" - 3.48" | 400 Crank: 3.75" | Gen. III 350 LS1: 3.62"
Rod Length Forged Steel 5.7" center to center - 5.565" 400 Rod - 5.940" Gen. II 265 CID L-99 V-8 - 6.098 Gen. III 350 LS1
Pistons Cast, hypereutectic or forged aluminum slipper skirt design
Lubrication Full pressure oiling, wet sump. Some Bowtie blocks offered for dry sump Gen. III uses crank-driven front generator pump.
Block Bores 3.50" - 4.126"
Bore Centerlines 4.040"
Cubic Inch Displacement 262 - 265 - 267 - 283 - 302 - 305 - 307 - 327 - 346(Gen. III) - 350 - 400
Compression Ratios 8.0:1 - 11.0:1
Induction 2-bbl - 4-bbl - inline 2 x 4-bbl - Crossram 2 x 4-bbl - Rochester Mechanical Fuel Injection - Throttle Body Fuel Injection (TBI) - Crossfire 2 x TBI - Tuned Port Fuel Injection (TPI) - Fuel Injection with Calloway Twin Turbochargers - Sequential Fuel Injection with mass airflow sensor.
Engine Weight Approx 550 lbs, all cast-iron and approx 450 lbs, all aluminum and Gen. III LS1
Main Bearings .002" - .003
Crank End Thrust .005" - .007"
Rod Bearings .002" - .0025"
Rod Side Bearings .010" - .020"
Piston to Bore Follow recommendation of piston maker
Valve Lash Follow recommendation of cam maker
Min. Piston Ring End Gap Follow recommendation of ring maker
Min. Piston Deck to Head Deck .035 - .040" with steel rods, more may be needed with aluminum rods
Open Valve to Piston Deck Minimum of .045" on a stock engine - .100" on a HP or race engine
Spark Plug Gap .035" with GM point ignition - .045" with GM HEI ignition - .035" - .060" with GM/MSD ignition
Cam End Play /w Cam Button .004" - .006"

Configuration Canted OHV V-8 Cast Iron or Aluminum blocks and heads
Cylinders (Front to Back) Drivers side: 1-3-5-7 - Passenger side: 2-4-6-8
Firing Order 1-8-4-3-6-5-7-2
Bore Spacing 4.84"
Crankshaft 5 main bearings, thrust on #5 (rear) cast or forged crank
Crankshaft Diameter Main Journal: (1-4) 2.7494" (5) 2.7488" - Rod Journal: 2.20"
Connecting Rods Forged steel, 6.135" centers - Big end diameter, 2.345" - Rod bolt diameter, 3/8" or 7 1/16
Pistons Forged & cast aluminum, slipper skirt
Lubrication Full pressure oiling
Bores 3.935" - 4.500"
Strokes 3.47" - 4.0"
Cubic Inch Displacement 366 - 396 - 402 - 427 - 454 - 510
Compression Ratios 8.25:1 - 12.5:1
Factory Induction 2-bbl - 4-bbl - 3x2-bbl Throttle Body Injection and Electronic Port Fuel Injection
Horse Power 215 HP to 465 HP (Factory ratings)
Weight Approx. 500 lbs, all aluminum or 750 lbs, all cast iron, complete

Tommy Ledberg