A Cheap Date: Zex in the Yard

Words And Photos: Richard Holdener

For performance guys on a budget, there is no better place to shop for a motor than your local LKQ, Pick-a-Part, wrecking yard, etc. All day, every day, you can go buy a complete, running Ford V8 (or other engine of your choice) for less than $300 (plus core). If you schedule your junkyard adventure on one of the sale weekends, where everything in the yard is 40 percent off, you can drop that number down to $180 (plus core). It’s pretty hard to beat a complete, ready-to-run V8 for less than 2 bills.

There are, of course, pitfalls to these great deals. You must choose wisely before pulling, or at least make sure you pony up for the warranty when purchasing. This protects you in the event your good deal was suffering from a spun bearing, broken lifter, or even a hole in the block. Never good to find this out after it has been installed. The other (less critical) downside to the wrecking yard route is you are (at best) buying a stock motor. If you are a Ford guy, there will be no Boss 302s, GT500s, or even 2003 Cobra motors to be had for chump change.

We did, however, manage to secure a nice 351 Windsor that, while hardly powerful in stock form, offered plenty of potential if modified (see Edelbrock Top End and Vortech articles).

Having made our choice and paid the fee, we immediately took the 1993 5.8L 351W over to Horsepower HQ (aka Westech Performance). The motor was stripped of the non-essentials (accessories, stock exhaust manifolds, and complete EFI induction). It is possible to run the motor with the factory EFI induction using a stand-alone management system (like the Fast XFI or Holley HP), but we decided on a carburetor for this test.

Running the carburetor allowed us to try the Zex Perimeter Plate system designed for a 4150 carbureted intake. To prep for the dyno, we installed a dual-plane, Qualifier intake manifold from Speedmaster, a Holley 650 XP carburetor and MSD billet distributor. We also installed a set of Hooker 1 ¾-inch, long-tube headers, and 18-inch collector extensions. Prior to testing, the motor also received five quarts of COMP Cams break-in oil, a K&N filter, and a fresh set of spark plugs.

Run with 35 degrees of timing and at 12.8:1 air/fuel ratio, the 351W produced peak numbers of 268 hp at 4,700 rpm and 338 lb-ft at 3,700 rpm.

It was obvious Ford designed this Windsor motor for a low-rpm truck application, with an emphasis on torque, but that doesn’t mean we can’t improve upon what was there. We’ve already tried an Edelbrock top-end kit and even a supercharger on our lat(er)-model Windsor with good success, but neither of those ranked as high on the low-buck scale as Zex Nitrous.

In keeping with our low-buck, Cheap-Date, junkyard theme, we decided to add the biggest, baddest, bang-for-the-bucker in existence. Yes, we were referring to none other than nitrous oxide. The Zex Perimeter Plate system featured 12 equally spaced injection points to ensure even distribution to maximize power. The kit also included the fuel and nitrous solenoids, a 10-pound bottle, and jetting to allow us to adjust the supplied power level. We made sure to heat the bottle in the Westech bottle heater prior to running.

After installation of 125-hp jetting, the 268 hp 351W was now a much-more impressive 386 hp small-block. Every bit as important was the fact the peak torque jumped from 338 lb-ft to 501 lb-ft. After swapping out the 125-hp jetting for 150-hp pills, the 351 produced 416 hp and 520 lb-ft of torque.

Considering the Zex kit can be had for something near $600, the amazing power gains made the Perimeter Plate system a Cheap Date indeed!

Equipped with the Holley carb, Speedmaster intake, and Hooker headers, the junkyard 351W truck motor produced 268 hp and 338 lb-ft of torque. The 1993 5.8L was hardly a powerhouse in stock configuration, but the Zex Nitrous stepped things up nicely. Equipped with 125-hp jetting, the nitrous-injected 351W produced 386 hp and 501 lb-ft of torque. The early engagement of the nitrous (before 4,000 rpm), resulted in huge torque gains.

This graph illustrates why Zex Nitrous is so awesome. Do you want more power? Just change the jets. In this case, we stepped up from 125-hp jetting to 150-hp jetting and were immediately rewarded with extra power and torque. The new jetting resulted in peaks of 416 hp and 520 lb-ft of torque. Using the Zex system, we improved the power output of the junkyard motor by over 50 percent for about $600.


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Power & Performance News

Power & Performance News is the source for news, tech and products that help you get more performance from your vehicle. If powertrain performance projects and hardcore technical content are your interest, Power & Performance News is the publication designed for you. Our acclaimed editorial staff covers all aspects of engine and driveline upgrades with a mission of presenting information that is both interesting and achievable for the “average car guy”.
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