Mustang MonthlyHow To Engine
FE Big-Block Performance Solutions
Make the most of your classic Mustang 390/428 experience
Although a wide variety of factory iron head castings exist for FE engines, in truth there isn't much difference between them. Most FE heads have 2.04/1.55-inch intake/exhaust valve sizes with slight variations in port and chamber size. The 428 Cobra Jet cylinder head, as one example, is virtually identical to the 427 Low Riser casting—and this is what Bob Tasca plucked off the shelf when he was developing the KR-8 (Cobra Jet) for his own Mustang in 1967. The 428 Cobra Jet was born from off-the-shelf 427 parts mostly coupled with the torque advantage that comes from the 428's increased stroke. Tasca saw the advantage in the 428's stroke topped with 427 Low Riser heads (2.09/1.66-inch intake/exhaust), a hot hydraulic flat tappet cam, and the 428 Police Interceptor intake manifold. The Cobra Jet was born to make lots of torque, which made it perfect for drag racing.
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Before you are the three basic FE cylinder head types explained by author George Reid. From the bottom up are the 427 High Riser, Medium Riser, and Low Riser. The 428 Cobra Jet cylinder head is on par with the 427 Low Riser. A better head is the 427 Medium Riser; which is a great compromise between Low Riser and High Riser. The High Riser is a racing cylinder head not suitable for street use.
New FE Blocks
When we received the call from Bear Block Motors (BBM) announcing the arrival of its new reproduction 427 cross-bolt side-oiler blocks, it was like an answer from heaven. We anticipated another high dollar all-aluminum FE block few could afford, but that's not what we saw. Imagine an all-new 427 cross-bolted, side-oiler iron or aluminum block with casting and machining quality way beyond anything Ford did in the 1960s. This is not marketing hype, but cold hard iron or aluminum virtually identical to what Ford was producing back in the day.
What makes the new 427 block better is vastly improved technology and a high-standard casting technique for starters. The BBM FE 427 block is cast with high tensile diesel grade iron with a super thick .750-inch deck. Siamese cylinder walls allow you to bore to 4.440-inches. Out of the box, bores are 4.245-inches, to be finish honed to 4.250-inches. An optional 4.150-inch bore will be available for the 428 crowd. Cross-bolted main caps are a perfect interference fit amid the block skirts without spacers. Locating dowels in the main saddles “lock” the forged and heat-treated 8620 steel main caps in place.
Down under are heavier, thicker main webs and pan rails for superior strength. What's more, these redesigned FE blocks accept both FE and Cleveland main bearings, which gives you a wider choice of performance bearings. Water jackets are cast solid, right up to the bottom of lower core plugs, to maximize cylinder strength and support. You may use standard ARP FE head bolts or studs. Main oil gallery passages are larger than the factory originals for increased oil volume. These BBM FE iron blocks tip the scales at 250 pounds. Prices have not yet been announced.
New FE Aluminum Block
BBM is producing an FE aluminum block for just $1,200 more than the iron that weighs just 125 pounds. Made from virgin high-density aluminum using the best casting technique in the world, the BBM aluminum 427 is a dry sleeve block, and sports centrifugally spun, high tensile strength, nodular iron flanged sleeves. Maximum bore is 4.320-inches, with decks finished to 10.155-inches. All this block needs is finish honing and you are good to go.
The 428 Cobra Jet cylinder head, as one example, is virtually identical to the 427 Low Riser casting—and this is what Bob Tasca plucked off the shelf when he was developing the KR-8 (Cobra Jet) for his own Mustang in 1967.
Cylinder Head Duo From BBM
Bear Block Motors introduces its new FE aluminum cylinder head for 390, 427, and 428 big-blocks with 2.150/1.680-inch intake/exhaust valves with lightweight 11⁄32-inch stems. Combustion chambers are engineered for optimum swirl and quench right out of the box. Intake ports offer 295-plus cfm. Exhaust ports yield 225-plus cfm of flow. High-swirl/high-quench chambers allow for more aggressive ignition timing on today's more unforgiving pump gas. Also available are CNC-ported FE aluminum heads with 2.25/1.71-inch valves, which calls for 4.230-inch minimum bore size. Expect to see 355-plus cfm intake and 250-plus cfm from these CNC-ported pieces.
Blue Oval Performance Engineering