Brodix Big Block Chevy BB-4 XTRA & BB-5 Series Aluminum Cylinder Heads

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. 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. !

VALVE SPRING   Specs   1.550'' Diameter Valve Spring for Mechanical Flat Tappet & Hydraulic Roller Lifter Cam Spring Pressure Open: 550 lbs. Spring Pressure Closed: 240 lbs. Installed Height: 1.950'' Max Lift: .700''   1.625'' Diameter Valve Spring for Mechanical Roller Lifter Cam Spring Pressure Open: 745 lbs. Spring Pressure Closed: 255 lbs. Installed Height: 2.050'' Max Lift: .800''   1.645'' Diameter Valve Spring for Mechanical Roller Lifter Cam Spring Pressure Open: 945 lbs. Spring Pressure Closed: 330 lbs. Installed Height: 2.100'' Max Lift: .875''