Racing improves the breed. It's a line that's both hopelessly cliché and devastatingly true. Let's examine the facts. Anytime a sanctioning body attempts to crack down on technological innovations, racers and engineers transcend these restrictions by refining an inherently rudimentary design beyond what anyone thought possible. For instance, when NASCAR banned overhead cams and roller valvetrains, teams responded with space-age cam lobe profiles, and incredibly lightweight yet durable valvetrain hardware that can now sustain 9,700-plus rpm with ease. For pushrod engines running flat-tappet lifters, it's a feat that's nothing short of astounding. Likewise, in the world of Outlaw 10.5 drag racing, limiting the maximum turbo compressor wheel diameter to 88mm has catapulted the power capacity of these huffers from 1,300 to nearly 1,700 hp in just a few short years. As a company that literally evolved with ultracompetitive late-model Mustang drag racing classes, Trick Flow knows all about working around rules restrictions. Its High-Port 240cc small-block Ford cylinder heads represent decades worth of refinements, culminating in intake ports that flow a stunning 343 cfm. Airflow figures like that beg the obvious question: Is it possible to crack the 700hp barrier in a pump-gas street motor with out-of-the-box cylinder heads? The answer is "hell yes" with another 31 bonus horsepower on top.
This month's dyno finale marks the third installment of PHR's "Revenge of the Windsor" series. To recap, the first two stories covered the assembly of our stout yet lightweight 454ci short-block. With a horsepower target of 700, a stock 351 Windsor block just wouldn't cut it. Furthermore, taking full advantage of the Trick Flow cylinder heads while maintaining a street-friendly rpm range required maximizing displacement as much as possible. Since this engine is destined to party in a street-driven '67 Mustang that moonlights as a road racer, Ford Racing's new all-aluminum Z351 block served as the perfect foundation for our engine build. Checking in at just 110 pounds—which is nearly 100 pounds lighter than an iron block of similar strength—the Z351 block can accommodate maximum bore and stroke dimensions of 4.125 and 4.250 inches, respectively. Maxing out those generous cylinder dimensions is exactly what we did, netting a big-block–like displacement tally of 454 ci.
Accompanying the Z351 block is a 4.250-inch forged crankshaft and 6.300-inch H-beam rods from Eagle, and custom 11.0:1 JE pistons. Since feeding a hungry 454ci short-block through 240cc intake ports can prove challenging at high rpm, we had Judson Massingill at the School of Automotive Machinists spec out a custom COMP solid-roller camshaft for our Windsor. Although the 268/280-at-.050 duration and .768/.748-inch lift figures of our custom camshaft may cause the limp-wristed to faint, big-block–sized displacement calls for a big-block–sized cam. At the risk of spoiling our test results prematurely, our Windsor's horsepower peak checked in at a grandma-approved 6,700 rpm on the dyno.
- Fans of the Ford Windsor small-block are probably more limited in the horsepower department than fans of any other small-block engine family. It is not for a lack of desire or ingenuity on their part either—there are just too many obstacles in the strength and airflow areas to overcome.
- When it comes to big power in a compact and lightweight package, there is nothing more tempting than building an engine starting with a top-shelf aluminum block. If there is any drawback, the cost factor can put such ambitions on the sidelines.