Ford’s famous Alphabet Cams (a.k.a. Letter Cams) have been around for decades and are often the go-to choice for Mustang owners looking for more performance from their 5.0L engine.
Ford Performance designed these cams for the 1985-and-up 5.0L/302 roller cam engines with 1.6 ratio rockers. On engines running electronic fuel injection (EFI), these camshafts are only compatible with mass air induction systems.
We’re going to look at four different cams from the “alpha” cam family: E303, B303, F303, and X303.
You can think of each cam as a performance tier, starting with mild street performance and ending with track use.
Here’s a quick overview of each cam’s basic qualities, and you can get the full spec breakout in the table below.
Ford Alphabet Cam Characteristics
The E303 adds mild performance improvements across the rpm range.
The B303 takes the performance up a notch without losing much streetability.
This cam makes power up to 6,200 rpm and is a good complement to forced induction (e.g. supercharging). You may have to modify your pistons for proper piston-to-valve clearance. (Recommended for manual transmissions.)
You’ll gain torque and power up to 6,500 rpm. Like the F303 cam note above, you should check valve clearance and modify your pistons accordingly.
Ford Alphabet Cam Specs
|Camshaft||Basic Operating Range (rpm)||Intake Duration at .050" Lift||Exhaust Duration at .050" lift||Intake Duration (Advertised)||Exhaust Duration (Advertised)||Intake Valve Lift||Exhaust Valve Lift||Lobe Separation|
For more specs, check out this data sheet from Ford Performance.
These camshafts require new valve springs. Ford Performance says you’ll need springs rated at a minimum pressure of 120 lbs. (closed) and 295 lbs. (open).
For automatic transmission applications, Ford Performance recommends a torque converter with higher stall rating than stock when using these camshafts.