Installing 557 Demon Stroker Kit - The Demon Stroker Kit For Big-Block Fords

Under all that dirt and grime sits a 460 Ford just begging for a little more displacement.

One of the best ways to start any engine build is with a power goal. It's also important to be honest (or at least realistic) about the intended application. Real (meaning daily-driven, pump gas) street motors that produce an honest 1,000 hp are rare-and for good reason. The odds are bad that someone will roll up next to you at a light with 950 hp wanting to street race. The other consideration is cost. Even if we decide that 1,000 hp is necessary, not many of us can afford to build such an animal, let alone pay for the fuel and maintenance required to keep it alive. Let's face it, most of us are on tight budgets and need to make do with the most basic buildups.

The 557 stroker kit came from Demon Engines and consisted of a 4.5-inch 4340 steel crank and a set of 6.7-inch (BBC) forged-steel rods from ProComp topped off with a set of flat-top forged pistons (4.44 bore) from Probe Racing. The pistons featured valve reliefs for the standard 460 valve configuration (shared by the ProComp aluminum heads used in this buildup).

The 557 stroker kit came from Demon Engines and consisted of a 4.5-inch 4340 steel crank a

Rather than go the easy Chevy route, we decided to take a look at what was available for the Ford guys-more specifically, for the big-block Ford guys. The Windsor crowd seems to get all the love recently, leaving the 429/460 Ford owners out in the cold. This big-block Ford never caught on with performance enthusiasts like the big-block Chevy did. The relative lack of desirability means there are plenty of rebuildable cores just rusting away in local wrecking yards. Don't bother looking for that Boss 429 or even a Cobra Jet-those are all long gone. In fact, don't bother looking under the hood of cars, period. Wander over to the area designated for trucks and marvel at all the big-block Ford performance just waiting to be unleashed. If your boneyards are anything like the ones here on the West Coast, most fullsize trucks in the yard will be sporting 460s. We like the idea of pulling a complete motor (or at least a long-block), since the assembly includes all the hard-to-find components such as a timing pointer, a distributor hold-down, and even the hundred or so retaining bolts Ford deemed necessary to secure the water pump. The local Pick-A-Part offered complete 460 Fords for the paltry sum of $245 (less $45 if you have a core). On special sale weekends, everything in the yard is 50 percent off.

As big-blocks go, the factory 460 Ford already sports some impressive displacement. Easily eclipsing the 440 Dodge, 454 Chevy, 455 Buick, and Pontiac offerings, only the massive 472- and 500-inch Cadillacs offer more displacement. The inches on the 460 come courtesy of a 4.36-inch bore combined with a 3.85-inch stroke. Though the big-bore combination suggests a candidate for high-rpm use (even more so for the smaller 429 with the 3.59 stroke), the 460 was primarily used for low-rpm towing and heavy hauling applications. As big as the 460 is in stock configuration, the best way to improve the power (and more importantly torque) output is to make it even bigger. A little math here goes a long way toward explaining the benefit of the extra inches. Suppose we choose a realistic power output of 600 hp for our street 460. Producing 600 hp from a 460 equates to a specific output of 1.304 hp per cubic inch, about the equivalent of a 400hp 302. Reaching this specific output with the 460 isn't a problem-it will just require sufficient compression, cam timing, and head flow. The downside of an elevated specific output is that the combination of compression, cam timing, and head flow might actually decrease driveability. In technical terms, the smaller the motor, the wilder the combination required to reach a given power output.

The affordable aluminum BBF heads from ProComp are available as cast or with CNC porting. The heads for this 557 featured full CNC porting on the intake.

The affordable aluminum BBF heads from ProComp are available as cast or with CNC porting.

One way around the driveability issue is through increased displacement. If we retain our goal of 600 hp but increase the displacement of our motor to 557 ci, we see that we have reduced the specific output to just 1.077 hp per cubic inch (the equivalent of a 325hp 302). It is not only much easier to produce 600 hp using a 557 than a 460, but the resulting combination will offer improved torque production, driveability, and engine life owed to the decrease in operating speed. A 600hp 460 will likely make peak power at or near 6,500 rpm, while the same power output from this 557 came in at just 5,600 rpm. Obviously, a stroker kit will cost more than pulling a used 460 from the wrecking yard, but not a lot more, since Demon Engines offers low-buck stroker kits (some as low as $1,800) designed specifically for the 460 Ford. The company's 557 stroker kit (other displacements are also available) for the 429/460 Ford consists of a 4.5-inch steel crank combined with a set of 6.7-inch forged-steel H-beam rods and forged flat-top pistons from Probe Racing. Different bore sizes are available, but this particular buildup features an increase in bore size from 4.36 to 4.44 inches. When combined with a jump in stroke from 3.85 to 4.5 inches, the result was an increase of nearly 100 ci (to 557 cubes).

The exhaust ports were likewise treated to CNC porting. Note also the use of ARP head studs to secure the Fel-Pro head gaskets.

The exhaust ports were likewise treated to CNC porting. Note also the use of ARP head stud

We followed along while Demon Engines assembled one of its stroker kits for a customer. This particular build included three upgrades that could be easily eliminated to reduce costs. They included a (mild) solid roller cam, a Weiand tunnel-ram, and a pair of CNC-ported ProComp aluminum heads. The ProComp heads were still high on the affordable scale, especially when you compare the flow rates with their stock cast-iron counterparts. But know that the 557 could be just as easily run with a single four-barrel intake, a hydraulic flat-tappet cam, and a pair of stock (possibly ported) iron 460 heads. The power output would be down somewhat with the stock heads, but the flat-tappet cam and single-four-barrel intake would work well on the larger motor.

Here is the assembled long-block ready for the remainder of the valvetrain and intake manifold. The front cover, oil pan, and stock damper were sourced from the core motor.

Here is the assembled long-block ready for the remainder of the valvetrain and intake mani

The owner set a realistic goal for this particular buildup of 600 hp. More important, the idea was for the stro-ker to offer a massive torque curve that easily exceeded 600 lb-ft, as having a veritable tidal wave of torque is considerably more fun and usable on a daily basis than having a big peak power number. Think about how much time your motor spends running at the power peak compared with those short bursts through the meaty part of the torque curve. Running a big-block like this will all but eliminate the need for downshifting to get the motor up on the cam. Traction will be much more of an issue than finding enough power to pass that pesky import.

With torque production in mind, the 557 was assembled using the Demon stroker kit, ProComp aluminum heads, and a Comp roller cam. The finished products offered a pump-gas-friendly static compression ratio of 10.3:1 (given the aluminum heads), and the tunnel-ram ensured plenty of visual appeal along with further improvements in the torque curve. With the crankcase full of Lucas Oil, the 557 eventually spit out our peak numbers of 615 hp at 5,600 rpm and 658 lb-ft at just 4,100 rpm. Torque production exceeded 650 lb-ft from 3,600 rpm to 4,600 rpm and remained above 600 lb-ft all the way out to 5,350 rpm. A similar Demon 557 stroker equipped with TFS A460 heads exceeded 900 hp in normally aspirated trim and more than 1,100 hp with nitrous, so you know the stroker assembly is plenty stout. All it'll take now is a phone call and/or a trip to the wrecking yard.