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The COPO 427 for A Stock competition uses the large-bore cylinder block and high-flow cylinder heads of the LS7 engine and complements them with a high-compression rotating assembly to deliver big power from its large displacement. Its lightweight aluminum block and heads revive the spirit of the original ZL-1 all-aluminum 427 big-block that helped forge the COPO legacy in 1969.
Specs:
Displacement: 427 cu in (7.0L)
Compression Ratio: 13.5:1
Cylinder Block: LSX Iron Block
Bore x Stroke (in): 4.125 x 4.100
Crankshaft: Forged steel
Connecting Rods: Forged steel
Pistons: Forged dome
Cylinder Heads: LS7 aluminum
Camshaft Type: Hydraulic roller
Camshaft Lift (int./exh.): .595/595-inch
ENGINE:
Chevrolet Performance LS7 aluminum block
4.125" bore x 4.00" stroke
Static compression ratio - 13:1 nominal
Callies 5140 crankshaft
Callies 4340 H-beam rods
6.100" C-C length
.928" pin bore diameter
Clevite H-Series heat-treated tri-metal rod and main bearings
Mahle 2618 alloy forged domed pistons
Graphal coating
Hard-anodized top ring groove
Friction-coated skirts
Mahle .043" x .043" x 3mm piston rings
Ductile iron top with radius molybdenum face
Plain cast iron tapered 2nd
Chrome-plated oil rails with low-tension expander
Chevrolet Performance steel billet hydraulic roller camshaft
Duration -- 233?/276? @ .050" lift
Theoretical valve lift -- .630"/.630"
Lobe centers -- 107?
VALVETRAIN:
Chevrolet Performance "Ceramic Ball" high-rpm hydraulic roller tappets
3/8" diameter LS7 pushrods
1.8:1 ratio LS7 rocker arms with roller trunions
PSI "Max Life" beehive valve springs
Hardened steel spring seats
Lightweight steel retainers
Fully CNC'ed aluminum cylinder heads -- based on LS7
275 cc nominal intake port volume
89 cc nominal exhaust port volume
70 cc nominal combustion chamber volume
Del West titanium intake valves -- 2.205" head diameter x 7mm stem
Lightweight sodium-filled exhaust valves -- 1.615" head diameter x 7mm stem
Fel-Pro Performance multi-layer steel head gaskets with raised cylinder sealing bead
Internal wet sump oil pump
Deep-sump cast aluminum oil pan --
6-quart capacity
SFI-approved damper
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