STS -18X Series Top End Kit
• Spread Exhaust Port
• 254cc Intake Ports
• 68cc Combustion Chambers
• 2.140'' Intake / 1.600'' Exhaust Valves
• 1.550'' Dia. Springs - 240# Seat Pressure
• Titanium Retainers
• Angle Plug
• Assembled, 2/pkg.
  
  
  Small Block Chevy Top End Kits Include:
• Complete Cylinder Heads
• HV 1800 Intake Manifold (4150 Series)
• Tall Cast Aluminum Valve Covers with Studs and Nuts
• Valve Cover, Intake, Exhaust, Carburetor and Head Gaskets
• Head Bolts with Washers
• Intake Bolts with Washers
• Spark Plugs
• Brodix Hat
  Cylinder Head Specifications
• Intake Port Volume: 254cc
• Combustion Chamber Volume: 68cc
• Valves: 2.140' dia. x 5.290' o.a.l. Intake / 1.600' dia. x 5.300' o.a.l. Exhaust ( 11/32' Stem Diameter )
• Valve Springs: 1.550' Diameter - Open Pressure: 550 lbs.; Closed Pressure: 240 lbs.; Installed Height: 1.950'; Max Lift: .700'
• Spring Retainers: 1.550' 10° Titanium
• Rocker Studs: 7/16'
• Guide Plates: 5/16'
• Valve Seals: 11/32'
• Spark Plug Configuration: Angled
  Facts and Related Components
• Torque Heads: 70 ft-lb.
• Torque Rocker Studs: 40-45 ft-lb.
• Intake Gasket: Brodix p/n 158-MG1800, Cometic p/n 245-C3250
• Head Gasket: Fel-Pro p/n 375-1003 (350ci) / 375-1004 (400ci) or Cometic p/n 245-C5399 (350ci) / 245-C5403 (400ci)
• Exhaust Gasket: Brodix p/n 158-MG52464 (trim to fit), Cometic p/n 245-C5424 (Spread Port)
• Head Studs: ARP p/n 070-234-4727 (12-point with 3/8' center studs)
• Spark Plug Specs: 14mm Thread, .750' (3/4') Reach, Gasket Seat
• Valve Angle: 18°
• Angle Milling: .0065' per cc
• Flat Milling: .0055' per cc
• Pushrod Slots: 40/60
• Stud Girdle: 40/60 Brodix p/n 158-BR6440
• Rocker Arms: Standard 7/16 Roller Rockers, Shaft System with 40/60 Spacing
• Lifters: Standard
• Pistons: Special 18°
• Pushrods: Special Length
• Intake Face Angle: 10° Standard
• Exhaust Pattern: Stahl only
• Valve Centerline: 40/60
• Spring Pockets: 1.550' Out of the Box, May be cut to 1.625' - No larger or deeper
• Accessory Bolt Holes are Drilled
• Recommended Intake Manifold: Brodix HV 1800 (p/n 158-HV1800) / HV 1801 (p/n 158-HV1801)

Emissions Note:

This part is only legal for sale and use on Uncontrolled (Non-Emissions Controlled) Vehicles or on vehicles used solely for the purposes of closed competition racing.

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