Ranking The Classic Ford Racing Letter Cams For Pushrod 5.0-Liter Engines

Back in the day, Ford Racing’s alphabet soup of camshaft options for the pushrod 5.0-liter engine was the go-to choice for Fox Mustang fans. However, selecting the one that best suits your combination has always been a head-scratcher. Today, many dedicated builders still swear by these highly affordable camshafts. To finally settle the score on these iconic grinds, The GT350 Garage host Walter Barber dove deep based on his 35 years of engine-building experience.

Barber started his definitive ranking by thoroughly addressing the early options originally released in the late 1980s and early 1990s. Placing the B303 dead last, he clearly explained that its terrible speed-density compatibility made it practically useless for real-world applications.

Despite selling thousands of units over the years, this beloved camshaft constantly delivered lazy low-end performance and fell completely flat by 5,500 RPM. “What you got with a B303 was a car that sounded like it should be fast, but wasn’t,” he explained.

Moving further up the list, the blower-specific F303 and the highly aggressive, out-of-production Z303 ranked fourth and third, respectively. The reliable E303 claimed the runner-up spot, primarily thanks to its excellent vacuum production and strict emissions compliance.

When it came time to pick an overall winner, the absolute top spot officially went to the highly versatile X303 camshaft. This grind had the same basic duration as the original B-cam but uses significantly more lift to snap the valves open aggressively. According to Barber, the secret of safely unlocking its massive performance potential involves intentionally altering the factory installation process.

By using a nine-keyway crank sprocket to retard the cam by exactly six degrees, builders can strategically shift the entire powerband higher. This surprisingly simple trick forces the engine to carry usable power deep into the upper rev range. “Retarding the camshaft is absolutely worthwhile. It makes more power, more usable power across a broader range,” Barber explained.

Winning Combination

Extracting maximum potential from the winning camshaft strictly requires specific supporting modifications. To start the build correctly, the spec sheet requires a healthy stock block with securely fitted modern piston rings for proper cylinder sealing. Builders must then carefully bolt down a set of Trick Flow Twisted Wedge cylinder heads, properly securing them with premium Fel-Pro head gaskets. Adding an extra 5 lb-ft of torque strictly to the top row of head bolts effectively prevents catastrophic gasket failure under heavy load.

However, making big horsepower on an engine dyno is meaningless if the vehicle cannot properly transfer that force to the pavement. A lightweight, 13-pound flywheel seamlessly paired with a close-ratio manual transmission effectively keeps the engine spinning freely right in its optimal powerband. For this specific high-revving setup, proper rearend gearing is absolutely critical. The combination warrants an aggressive 4.10 or 4.30 gearset to ensure the car crosses the finish line at peak horsepower.

Strictly Tuned

Barber also provided strict instructions for the final computer calibration. Specifically, the Trick Flow combustion chambers require exactly 32 degrees of total timing and a perfectly steady air/fuel ratio in the mid-12 range to operate safely on standard premium pump gas.

Following this incredibly exact mechanical recipe consistently produced solid real-world results on both the street and the drag strip. For example, one Fox Mustang using this exact combination consistently ran high 11-second quarter-mile passes, while retaining excellent daily drivability and functioning air conditioning. That same car made 352 horsepower to the rear wheels.

This highly educational ranking shows that massive popularity does not always translate into maximum performance. By intelligently choosing the absolute best available grind out of the classic Ford Racing letter cams lineup, pushrod 5.0-liter builders can successfully unlock the hidden potential of the iconic 5.0-liter platform with period-correct mods.