World Products has developed these packages for the performance enthusiast who is faced with rebuilding a 396, 427, 454 or 502 cubic inch Chevrolet big block and would like to gain some serious displacement at virtually no extra cost! Just ad an intake, exhaust and ignition system and you’re on your way to a 500+ horsepower engine combination with stump-pulling torque! It features a MERLIN III cast iron block, a digitally balanced rotating assembly consisting of a 4340 forged steel crank and H beam rods, forged aluminum pistons and high performance rings. The MERLIN cast iron (Stage 1) or aluminum (Stage 2) heads are assembled exclusively with Manley stainless steel valves and are topped with aluminum rocker arms.

Engine Block: World Products Merlin III cast iron, Merlin X aluminum
Deck Height: 9.800” (509, 540), 10.200" (572, 632)
Bore/Stroke: 4.500” x 4.000” (509), 4.500" x 4.250" (540), 4.500" x 4.500" (572), 4.600" x 4.750" (632)
Main Caps: 4-bolt nodular splayed
Cylinder Heads: Merlin Oval Port 269cc cast iron (Stage 1), Merlin III 350cc aluminum (Stage 2)
Valves: Manley stainless steel
Timing Chain: Double roller
Crankshaft: 4340 Eagle internally balanced
Connecting Rods: 4340 Eagle
Pistons: Mahle
Gaskets: Felpro
Internal Hardware: ARP
External Hardware: Totally Stainless
Oil Pan: Moroso (Stage 2 only)

Compression Ratios
509 Stage 1: 9.5:1
509 Stage 2: 9.5:1
540 Stage 2: 9.5:1
572 Stage 2: 10.8:1
632 Stage 2: 10.4:1