Boosting The Power Of A 351-Cube, Junkyard Small-Block

Modern Ford performance is alive and well, just ask any late-model Mustang owner. While the current crop of Coyote 5.0-liters are impressive performers, you are not as likely to find one at your local wrecking yard. Even if you were to come across a Coyote for sale, it would be considerably more expensive than the many 351 Windsors we found on our latest trip to the junkyard.

There were no Coyotes to be had, and only a few mod motors (all of which were the Two-Valve 4.6- and 5.4-liter variety), but the yard was full of the fuel-injected 5.0- and 5.8-liter Windsor motors. Sure, the early small-blocks can’t compete with a Coyote (or mod motor) in stock trim, but the one thing they have going for them is tremendous aftermarket support.

…The answer to any performance question is almost always “boost.”

Couple the availability of upgrades with endless years of research and development performed by enthusiasts, and you have the makings of a mild motor just begging to get wild. To illustrate the hidden potential of an injected 351 Windsor, we upgraded a 5.8-liter V8 with better hardware then added boost. The result was one impressive street motor, with plenty left on the table should you decide to get serious.

For those that might be new to the performance world, the answer to any performance question is almost always “boost.” Whether it’s street or strip, stock or modified, everything is better with boost. The only thing cooler than boost is (of course) intercooled boost. To drive this point home, we applied intercooled boost to a 351 Windsor.

Boosting Performance

In this case, a Vortech V3 Si supercharger supplied that boost. On paper, the V3 certainly looked impressive, capable of flowing 1,150 cfm, delivering up to 22 psi and producing upwards of 750 horsepower (a rating we know to be on the conservative side). None of those upper limits would ever come into play on our Windsor, but it was nice to know the V3 Si offered such high adiabatic efficiency (meaning lower charge temps under boost). Naturally, we also liked the self-contained oiling that eliminated the need to supply a high-pressure feed or provide a drain-back in the oil pan.

Boost from any source can best be described as a multiplier of the normally aspirated power. The more powerful the normally aspirated combination, the more power it will make under boost. Knowing this, we made sure the 351 Windsor was plenty powerful before adding the Vortech. Starting with a high-mileage, junkyard 5.8-liter, we retained the stock short-block, but augmented the induction with components from Edelbrock and COMP Cams.

Vortech V-3 Si Performance Specs

Internal Step-Up Ratio: 3.61:1

Max Speed: 52,000 rpm

Max Boost: 26 psi

Max Flow: 1,150 cfm

Max Power: 775 horsepower

Peak Efficiency: 78 percentWe swapped out the stock truck cam in favor of COMP’s Xtreme Energy 282. The XE282HR features a .565/.574 lift split, a 232/240-degree duration split and 112-degree lobe separation. The cam was teamed with a set of Edelbrock’s E-CNC 185 heads retained by ARP fasteners. As their name implies, these heads featured 185cc intake ports that flow a whopping 292 cfm, enough to support 600 horsepower on the right application. Feeding the heads is an Edelbrock Performer RPM II upper and lower intake fitted with a set of FAST 36-lb/hr injectors, an Accufab 75mm throttle body and a Holley HP fuel-injection system.

Natural Progression

Before installation of the supercharger, we ran the modified 351W on the dyno using a set of 1 ¾-inch Hooker headers, an MSD distributor and a Meziere electric water pump. With this configuration, the naturally aspirated 351W delivered peak outputs of 418 horsepower at 5,800 rpm and 423 lb-ft of torque at 4,700 rpm.

At this boost level, the supercharged and intercooled 351W produced peak numbers of 626 horsepower and 577 lb-ft of torque.

With a proper baseline recorded, it was time for some boost. We made short work of installing the Vortech V3 onto the awaiting Windsor, including the air-to-water Maxflow Powercooler. Though we ran other pulley combinations, the best results came from a 3.0-inch blower pulley run in conjunction with the supplied 6.0-inch crank pulley. This produced a 2:1 drive ratio for the blower. When we combined this with the internal step-up ratio of 3.6:1 and 6,000 rpm engine speed, the pulley combo produced a maximum impeller speed of 43,200 rpm. This was well below the 52,000 rpm limit recommend by Vortech, and resulted in a maximum boost pressure of 8.5 psi.

At this boost level, the supercharged and intercooled 351W produced peak numbers of 626 horsepower and 577 lb-ft of torque. Datalogging during the run indicated that the intercooler was knocking over 70 degrees of charge temperature out of the charge air (from 88 to 159 degrees). We did notice a slight drop in boost across the core as well, an indication that it might be time to look for a larger core if you plan to max-out your Windsor, but for now, this supercharged 351 was one cool customer.

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