Big block engines demand large airflow capabilities from their induction systems in order to make the most horsepower. The latest entry into the big-block Ford world comes from Air Flow Research (AFR), with its new big-block ford 14 degree cylinder heads.
These heads are available in 270cc, 285cc, and 300cc intake volumes. The exhaust ports on the 300 and 285 heads are 142cc while the 270 version has a volume of 132cc. The heads feature a 14 degree intake valve angle and 8 degree exhaust valve angle, and are offered in either standard or 0.250-inch raised ports.
We spoke with AFR’s Tim Torrecarion about these new heads at the 2015 SEMA Show. “The biggest thing we were trying to address was the poor port design of the OEM castings. We went to more of a ‘roval’ or rounded oval type design. Also we went to a more consistent cross-sectional area, which wound up improving the flow. We moved the valve locations to unshroud them and free up the flow into the bowls.”
The 300cc heads feature 2.300 intake and 1.760 exhaust valves, and can flow as much as 427 cfm at 0.750 lift on the intake side. The 285cc heads use 2.25 intake and 1.760 exhaust valves and can flow 411 cfm at 0.700 lift. The smallest of the batch is still no slouch, with the 270cc heads utilizing the same valves as the 285cc versions, but flowing 390 cfm at 0.650 lift. All of the heads are available with either 85cc large volume combustion chambers, or 75cc small chambers.
Torrecarion says AFR offers custom milling in either flat or angle on all versions of this cylinder head. The heads are also available completely assembled with valvetrain setup for either hydraulic roller or solid roller camshafts. The solid roller valve train is good for up to 7,600 rpm and 0.750 lift camshafts off the shelf. The hydraulic version is good for 6,700 rpm, and up to 0.725 lift.
Torrecarion says AFR saw significant gains on the dyno when testing these heads. A fully assembled pair of the 300cc version in large chamber has a MSRP of $3,100 per pair.
In order to maximize its offerings to customers, AFR also developed a new big-block Ford intake manifold to compliment its news cylinder heads. This manifold features a unique runner design. “One of the biggest things we did here was try to equalize the runner lengths,” says Torrecarion. “We tried to equalize the runners by manipulating the size and the lengths so that we can get similar flow numbers on each port going into the heads.”
Torrecarion says that the intake is matched to the cylinder heads. “Another thing is the port profile is designed to match perfectly with our porting. If you have an existing manifold from another brand, you will give up a few horsepower.”
The new intake is offered with either a flange for a 4150 or 4500 style carburetor.