By Richard Holdener

Ford has introduced some serious modern muscle in the form of the four-valve Coyote, but let’s not forget the original 5.0L fuelie that started the Ford revolution back in 1986. Sure, Ford offered the 5.0L (and even 302s) prior to 1986 but it wasn’t until the advent of fuel injection that things seemed to take off on the fast Ford front. Stock for stock, the old 225 horsepower 5.0L is no match for its 400+ horsepower, mod-motor counterpart, but that doesn’t mean there aren’t still a ton of the originals out roaming the streets and strips of this great country. The original, and continued popularity of the 5.0L fuelie is no accident. Though limited in terms of output compared to the current crop of wonder motors (from Ford, Chevy and Dodge), they were plenty sporty back in the day. Toss in the fact that not only were they plenty powerful in stock trim, they also earned a reputation for responding quite favorably to any of millions of after market performance parts. It was, however, the 5.0L that started the revolution and just like back in the day, creating a top-end terror is just a few upgrades away.

To illustrate just how well these 5.0L motors respond to performance upgrades, we decided to put one through a series of tests. The idea was to run the motor in (near) stock trim, then again after subjecting it to a top-end package, namely the heads, cam and intake. Though there is certainly power to be had from the short block, oiling system and exhaust, the heads, cam and intake are the major power players in any build up. To properly test this, we first needed a suitable test motor. Since a healthy dose of nitrous was also on the list, we needed something better than just a junkyard jewel. To that end, we built a dedicated 5.0L capable of withstanding not only the normally aspirated performance mods, but also the extra 100 horsepower supplied by our ZEX Wet EFI nitrous kit. Starting with a factory 5.0L hydraulic roller block, we combined a forged steel crank from RPM with a set of forged rods from ProComp and flat-top, forged pistons from Probe Racing. Though the stock block was still the limiting factor in terms of absolute power production, this forged assembly insured plenty of strength for nitrous use.

The flat-top pistons yielded a static compression ratio of 9.35:1 with the 64cc chambers in the stock heads. In addition to the stock E7TE Ford heads and cam, the baseline numbers were generated with a GT-40 intake and Accufab throttle body. Also present was a set of Hooker 1 ¾ inch (Fox chassis) headers, a Meziere electric water pump and FAST XFI management system. All testing included an MSD billet distributor and ignition amplifier, Lucas 5W-30 oil and FAST 36 pound injectors. Because the stock E7TE iron heads had previously been modified to accept a screw-in rocker studs, we took the liberty of installing a set of 1.6 ratio, self-aligning roller rockers. The 5.0L build also included new hydraulic roller lifters, a double roller timing chain and hardened pushrods (6.25 inch) all from COMP Cams. Other than the screw-in studs and a spring upgrade, the head ports, chambers and valve job remained completely stock–meaning they preformed just like a stock set would in terms of flow and power.

Basically we had a 5.0L with a forged rotating assembly topped off with a set of stock heads, stock cam and GT-40 intake. The heads, cam and intake upgrade planned for the 302 included a set of CNC-ported, RHS Pro Elite 205 heads, COMP XE274HR cam and Holley SysteMax intake. The Pro Elite heads featured 205cc intake valves, a 2.055/1.60 valve package and 62cc combustion chambers. Capable of supporting nearly 600 horsepower, they were more than adequate for the flow needs of our modified 5.0L. The XE274HR cam (pt# 35-518-8) offered a .555/.565 lift split, a 224/232 degree duration split and an EFI (and blower and turbo) friendly 112-degree lobe separation angle. Topping things off was an Extrude Hone ported Holley SysteMax intake. The Extrude Hone process (forcing abrasive media through the ports) was ideal for long-runner intakes where access to the runners made conventional porting difficult. The head, cam and intake upgrade also included a set of ARP head studs and Fel Pro head (1011-2) and intake (1262) gaskets.

First on the to-do list was to run the 5.0L with the stock heads, cam and GT-40 intake. Testing showed that the GT-40 intake was worth nearly 20 horsepower over the stock 5.0L H.O. intake, though there was a slight trade off in low-speed torque. Tuned with the FAST XFI management system, the forged 5.0L produced 279 hp at 5,300 rpm and 323 ft-lb of torque at 3,400 rpm. Better known for torque than high-rpm horsepower, torque production from the H.O. 302 exceeded 300 lb-ft from 2,800 rpm to 4,700 rpm. After installation of the RHS head, COMP Cam and Holley SysteMax intake, the peak numbers jumped to 395 hp at 6,200 rpm and 380 lb-ft of torque at 5,000 rpm. Though the mods shifted the torque curve higher in the rev range, the modified 302 exceeded 350 lb-ft of torque from 3,900 rpm to 5,900 rpm, and never dipped below 300 lb-ft. Both the heads and intake would support considerably more power, but the (relatively) mild 274 cam offered a nice balance of power and drivability. Stepping up in cam would certainly trade low-speed power at this point, but there was one way to add power without such a trade off–enter ZEX nitrous.

The top-end package had pushed the modified 302 close to 400 horsepower, but that was still a far cry from the 500 horsepower we were looking for. Wanting that big jump in power, we naturally turned our attention toward nitrous oxide. Nothing adds power as easily and inexpensively as a little squeeze. Quite literally at the push of a button, it is possible to add 100 horsepower (or more) to just about any combination. For this test, we installed 100 hp jetting in the ZEX Wet EFI kit. This trick kit combined nitrous and fuel into a single fogger nozzle, which we mounted in our air intake in front of the Holley throttle body. The adjustable ZEX kit included everything needed to add from 75 hp-125 hp to just about any injected motor. The ZEX kit was unique in that it featured a controller capable of learning the TPS voltage curve. This ensured nitrous activation would only occur at WOT, though it did not eliminate activation at lower engine speeds (very bad idea). Engaging the nitrous too early in the rpm range can wreak havoc on your engine. Adding the nitrous to our 5.0L motor increased the power output from 395 hp and 380 ft-lb of torque to an impressive 506 hp and 547 ft-lb of torque. Combining the heads, cam and intake with the ZEX nitrous transformed this 302 into one serious top-end terror.

Replacing the GT-40 intake, stock 5.0L heads and cam with the ported Holley SysteMax, RHS Pro Elite heads and COMP XE274HR cam resulted in a huge jump in power. Equipped with the stock components, the 302 produced 279 hp at 5,300 rpm and 323 ft-lb of torque at 3,400 rpm. After the to-end upgrade, this jumped to 395 hp at 6,200 rpm and 380 lb-ft of torque at 5,000 rpm. The to-end package offered not only more power but extended the usable engine speed up to 6,500 rpm.

The heads, cam and intake mods offered some serious power gains but the best way to get an extra 100 horsepower is with nitrous. Adding the ZEX Wet EFI kit offered serious power gains, taking the peak numbers from 395 hp and 380 lb-ft of torque to 506 hp and 547 ft-lb of torque. Best of all the additional power came with no penalty in idle quality or drivability.

Sources

Accufab
1 (909) 930-1751
accufabracing.com

COMP Cams
(901) 795-2400
compcams.com

Holley/Hooker
(270) 782-2900
holley.com

L&R Automotive
(562) 802-0443
lnrengine.com

Pro Comp Electronics
(909) 605-1123
procompelectronics.com

RHS Cylinder Heads
(877) 776-4323
racingheadservice.com

RPM International
1 (562) 926-9188
racingpartsmaximum.com

ZEX Nitrous
1 (888) 817-1008
zex.com