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- STS BB-4 XTRA Series Cylinder Head
- CNC Ported
- 390cc Rectangle Intake Ports
- 119cc Combustion Chambers
- 2.350'' Intake / 1.900'' Exhaust Valves
- 1.625'' Dia. Springs - 255# Seat Pressure
- Titanium Retainers
- Assembled, 1/pkg.
Cylinder Head Specifications - Intake Port Volume: 390cc - Rectangle Port
- Combustion Chamber Volume: 119cc
- Valves: 2.350' dia. x 5.568' o.a.l. Intake / 1.900' dia. x 5.494' o.a.l. Exhaust ( 11/32' Stem Diameter )
- Valve Springs: 1.625' Diameter - Open Pressure: 745 lbs.; Closed Pressure: 255 lbs.; Installed Height: 2.050'; Max Lift: .800'
- Spring Retainers: 1.625' 10° Titanium
- Rocker Studs: 7/16'
- Guide Plates: 3/8'
- Valve Seals: 11/32'
- Spark Plug Configuration: AngledFacts and Related Components
- Torque Heads: 70 ft-lb.
- Torque Rocker Studs: 40-45 ft-lb.
- Intake Gasket: Brodix p/n 158-MG2001, Cometic 245-C5428, Fel-Pro 375-1252-3
- Head Gasket: 4.540' Bore - Fel-Pro p/n 375-1017, Cometic p/n 245-C5433; 4.600' Bore - Fel-Pro p/n 375-1057, Cometic p/n 245-C5434
- Exhaust Gasket: Fel-Pro p/n 375-1411 or Cometic p/n 245-C5429
- Head Bolts: ARP p/n 070-135-3606, Manley p/n 660-42192
- Head Studs: ARP p/n 070-235-4702 (12-point)
- Spark Plug Specs: 14mm Thread, .750' (3/4') Reach, Gasket Seat
- Valve Angle: 24° and 4° Intake, 15° and 4° Exhaust
- Angle Milling: .0066' per cc
- Flat Milling: .0050' per cc
- Pushrod Slots: Standard
- Pushrods: Check pushrod clearance with head installed on the engine block before final assembly
- Stud Girdle: Standard
- Rocker Arms: Standard
- Lifters: Standard
- Pistons: 2° Valve Rolled Piston
- Valve Centerline: Standard
- Exhaust Pattern: Raised .600'
- Spring Pockets: May not be cut any larger or deeper than 1.625'
- Accessory Bolt Holes are Drilled
- Recommended Intake Manifold: Brodix SA 2012 (p/n 158-SA2012) / SA 2020 (p/n 158-SA2020)
Raised Intake and Exhaust Port Design!
24°/4° Intake & 15°/4° Exhaust Valve Angles
The Brodix BB-4 XTRA and BB-5 valve angles have been rolled 2-degrees from stock to produce more torque and less chamber volume. The BB-4 XTRA and BB-5 have a raised, rectangle-shaped intake port design (approximately .400'') allowing the short-turn radius a better air flow angle without sacrificing velocity. Others offer a similar version of these heads, but they have larger intake ports in the stock location. The competitor's low profile head slows down the air speed making the engine extremely lazy.
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The BB-4 XTRA heads are 100% CNC ported intake/exhaust ports, combustion chambers and fully blended bowls that flow an amazing 447 cfm and raised exhaust ports that flow 276 cfm with a 1.900'' exhaust valve.
When Sonny Leonard designed the BB-5 cylinder head for larger cubic inch engines, he incorporated the most important things: correct port shape, volume, and velocity. The BB-5 have CNC'd intake port match, fully blended bowls and valve job. The intake/exhaust ports and combustion chambers remain as-cast. If you want to take the next step up from a standard 26/4 and 17/4 valve angle cylinder head, the Brodix BB-4 XTRA or BB-5 is the ticket! Standard features include an extra thick deck, high valve cover rail, and the best castings in the business.
Every casting is poured from A-356 virgin aluminum and tested before Brodix utilizes their in-house processes such as finish machining and heat treating to assure that you receive the best products for your hard-earned money. Other features include a thick deck surface that is compatible with nitrous, drilled and tapped holes on the ends for standard drive accessories, phosphorous bronze valve guides and hardened valve seats installed for unleaded fuel. Sold Individually, 1/pkg.
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