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//12° BIG DUKE


To create the 12 Degree Big Duke performance cylinder head, MBE pulled together lessons learned from its winning NHRA and IHRA Pro Stock programs along with its 18 record-holding Comp Eliminator customers to develop ports that are perfectly sized to both maximize airflow and port velocity. With 2.500-inch intake valves and 1.860-inch exhaust valves installed in combustion chambers than can be sized anywhere between 68 and 78 cc’s, the precisely designed ports flow an astounding 560 cfm through the intake and 354 out of the exhausts. And remember, MBE is the only induction specialist willing to stand behind its advertised flow numbers with a guarantee that you will see the same or better performance on your own flow bench.


MBE’s 12 Degree Big Duke cylinder head is a great option for throttle stop racing, such as Super Comp or Super Gas and also works extremely well in nitrous applications. Some racers currently racing—and winning—with these heads include Steve Williams, Tommy Phillips and Doug Bracey. And more are using MBE’s 12 Degree Big Duke heads to join the ranks of the victors at the race track every week.


To squeeze the absolute most power out of your engine combination, MBE also produces a cast intake manifold custom ported to perfectly match the characteristics of the cylinder head. To put it simply, this is the best 12 Degree Big Duke cylinder head you can buy for big cubic inch engine packages (typically 565 to 700 cubic inches), especially if you need a head that keeps making power at rpm levels that are way beyond the point that the competition has flatlined.


Intake Valve Diameter: 2.500

Exhaust Valve Diameter: 1.860

Combustion Chamber: 

Volume: 68 to 78 c.c. Nitrous

Seats: Copper Beryllium or Steel

Minimum Bore: 4.480

Intake Manifold: MBE Ported Edelbrock (or) Sheet Metal

Rockers: T & D or Jesel

Complete Assemblies Available


(additional to base price)


Intake valves: Titanium .

Exhaust valves, Titanium .

Seats: (16) Copper Beryllium 

Retainers: Titanium Retainers .

Locks: Titanium Locks, , Steel Locks, .

Spring ID Locator, 

Lash Caps, 

Valve Seals, 

Rockers: T&D Alum. ., T&D Steel ..

Jesel, call for price

Coat Valves: (8) .

CC & Deck, 


Manifold: Intake, 


Carb Spacers, (1) 

Springs: Call



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