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Supercharged 427 Windsor Vs. ZEX 557 A460 Stroker - Goliath's Revenge
We Pit A Blown 427-Inch Windsor Against A Juice-Gulping 557-Inch Big-Block.
Call it what you will-David versus Goliath, brawn versus brains, or in our case, inches versus pounds-but regardless, it's the little guy taking on the insurmountable task of overwhelming the big guy.
In nature, bigger is usually better, meaning the big animals eat the little ones. In the horsepower game, more displacement is often better than having less. As the classic story goes, Goliath had free reign because there was no one big (or brave) enough to stand up to him-until he met little David. What David lacked in size, he more than made up for in weaponry.
When it comes to making power, bigger motors make more power than smaller ones because they can process more air and gas. While the Goliath-based logic seems sound, the statement does not take into account the automotive equivalent of David, his was a bag of smooth stones and fancy sling, ours is one you're familiar with-boost!
A Supercharged All-Aluminum 427 Windsor
Like its biblical brethren, our automotive David combines light and might. The light portion came from our choice of a Dart aluminum 351W Ford block. This block scores high on the cool and power-to-weight ratio scales.
Improvements on the other end of the power-to-weight scale came from a stroker version thereof. David was fortified with a 4.00-inch steel stroker crank courtesy of Pro Comp. Pro Comp also supplied a set of 4340 forged connecting rods, which were combined with a set of forged flat-top pistons from Probe Racing.
The aluminum 427 stroker short-block was machined by L&R Automotive and professionally assembled by Demon Engines. It is interesting to note that the use of flat-top pistons on a motor of this displacement usually means you have a static compression ratio exceeding 12.25:1, but we reduced static compression ratio to a street-friendly 10.3:1 using a rather large combustion chamber. The normal consideration is drivability versus power. Wilder cam timing (high-lift and long-duration) will result in higher peak power numbers, but these numbers generally occur higher in the rev range. Unfortunately for enthusiasts, the cost of all that wonderful top-end power is almost always a reduction in low-speed torque production.
But rather than go with the typical hydraulic roller, we chose a solid roller profile. To reach our goal of 1,000 hp, we wanted to maximize the output of the normally aspirated motor, then add as little boost as necessary to safely reach our goal. We selected a custom solid-roller profile from Cam Research Corp (www.camresearchcorp.com). After providing our specs and power needs, Cam Research Corp supplied us with an aggressive roller profile that offered a 0.692/0.684-lift split, a 254/252 duration split at 0.050 and a blower-friendly lobe separation angle of 112 degrees. The roller cam was combined with a set of PN 838-16 roller lifters from Comp Cams.
Once David had sufficient displacement and cam timing, we turned to head flow. Not surprisingly, head flow is one of the key ingredients in the power production of any motor, regardless of displacement. And the head flow must work in conjunction with the cam timing and intake design, as the combination helps dictate horsepower and torque peaks, as well as the shape of the overall curve.
With this in mind, we chose CNC-ported Trick Flow High-Port 225 cylinder heads. Impressive even in as-cast form, the High-Port 225 heads feature 2.08-inch intake valves and 1.60-inch exhaust valves, full CNC porting, and careful hand blending, which combine to produce impressive flow figures. The 225cc intake ports flowed 335 cfm at 0.700 lift, while the exhaust flow checked in at 258 cfm at the same valve lift. Though not relevant for most street motors, the 0.700-lift flow figures were important to us since our Cam Research roller cam offered right near 0.700 lift on both the intake and exhaust. The High-Port heads were set up with a suitable valve spring package to accommodate our near 0.700-lift roller cam and topped with titanium retainers.