RHS LS 9.240" Standard Deck 4.120" Bore Aluminum Race Block 54903U

Block Specifications

• Designed from heavy-duty A357-T6 aluminum material

• 3.895”-4.165” siamese cast bore walls w/ press-in spun cast iron liner

• Available in standard (9.240”) & tall (9.750”) deck heights w/ beefy .750” deck thickness

• Both standard deck (5.67”/5.87”- same as LS7) & tall deck (5.94”/6.38”) cylinder liner lengths available

• “Long arm friendly” – Accommodations for up to 4.6” stroke w/ standard rod pin diameters (2.100”) & oversized 60mm camshaft

• Raised cam centerline (.388”/9.86mm) to allow larger stroke; 2 extra links in the timing chain – Timing sets available from COMP®

• Main cap surface area maximized at mating surface & large fillets from cap to cross bolts for added strength

• Designed for clearance – side oil galley moved outboard & engineered rod clearance come standard

• Significantly increased windage passage area under bores & around caps over LS7/LSX engines

• 6 head bolt design w/ full water jacket around the cylinders (based on LS7 design)

• Bay-to-bay breathing improved w/ increased side window area versus LSX & LS7

• Extra large windows in valley for access to inboard “6th” head bolt

• Extra long liners for standard (5.87”) & tall (6.38”) decks

Valve Train Capabilities

• Provisions for Gen III & Gen IV cam & knock sensors & valley covers

• Cam tunnel will accommodate stock through oversized 60mm roller bearing cams (includes cast-in lock screw pads)

• .842” lifters standard with material available for oversized lifter access (accepts 1.060” bushing for keyed lifters)

• In the standard deck, maximum pushrod angularity = Less than 2 degrees

• Includes Ampco 45 cam thrust plate and aluminum rear cover

• Lifter bosses designed to clear tie bar lifter

Oiling Features

• Priority main oiling, galley moved outboard for long stroke clearance

• Oil filter feed galley GM “dog bone” replaced with proprietary no restriction threaded plugs

• Dry sump friendly with provisions for more serious dry sump setups; includes big front & rear AN-12 side feeds

• Includes provision for piston oil squirters, cast-in & machined

Additional Features

• Rolled threads on all threaded holes for added strength

• Gen III/Gen IV compliant with race mounts for Gen I, Gen II, Gen III & Gen IV engines

• ARP main stud kit standard with enough material in castings to accommodate up to a ½” fastener

• Chilled main bearing bulkheads for added strength

• Optimized billet main caps & improved windage