Racing Head Service (RHS) 54903U - LS Block, Std 9.240" Deck, Ready To Hone To 4.120"

BLOCK SPECIFICATIONS:
- Designed from heavy-duty A357-T6 aluminum material
- 4.125”-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

SUPERIOR OILING:
- 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