Richard Holdener
July 5, 2013

Engine Specs-Modified 5.0L H.O. (EFI)
Displacement 306 ci
Bore 4.03
Stroke 3.00
Pistons Stock H.O.
Forged Yes and no—depends on year
Compression 9.2:1
Rods Stock H.O.
Forged No
Heads RHS Elite CNC
Alum Yes
Iron No
Ported Yes
Intake Valve 2.055-inch
Exhaust Valve 1.60-inch
Chamber Size 62cc
Upper Intake Holley SysteMax
Ported No
Lower Intake Holley SysteMax
Ported No
Throttle Body 65mm Accufab
Injector Size 36-lb/hr
Fuel System Aeromotive
EFI System Holley Dominator
MAF Stock Ford (not used on engine dyno)
Custom Chip No
Distributor Stock (MSD used on dyno)
Header (style) Hooker Super Comp long-tube
Header Size 13⁄4-inch
Cam Crane hyd-roller (hyd/solid-roller)
Intake Lift 0.542
Exhaust Lift 0.563
Int Dur Degrees 224 @ 0.050
Ex Dur Degrees 232 @ 0.050
LSA 112
Rockers Crane Gold roller
Ratio 1.6:1
Exhaust 2.5-inch with Borla mufflers
Max Power Output (dyno) 395 hp @ 6,200 rpm
Max Torque Output (dyno) 380 lb-ft @ 5,000 rpm

5.0L Stock vs. Modified 302 EFI

These two graphs illustrate the power gains offered by typical bolts-ons to a 5.0L Ford. We have included the horsepower and torque graphs for a bone-stock 5.0L as a reference. Run in stock trim with no accessories, a set of Hooker headers, and tuned with a Holley EFI system, the stock 5.0L EFI motor produced 232 hp at 5,100 rpm and 306 lb-ft of torque at 3,400 rpm. After swapping on a set of CNC-ported heads from RHS, a Crane 224/232 cam, and Holley SysteMax intake system, the power jumped to 395 hp at 6,200 rpm and 380 lb-ft at 5,000 rpm. The number of performance packages that have been applied to the otherwise-stock short-block is staggering, but this is a good example of what can be expected. There is additional power to be had with wilder cam timing, but figure you will start to trade bottom end torque for the gains experienced higher in the rev range.

12. The combination of the Edelbrock intake, Crane cam, and CNC-ported heads produced excellent results. Of course the Scat crank, rods, and JE pistons were a big part of the equation, but the EFI 347 produced 463 hp at 6,200 rpm and 435 lb-ft of torque at 4,500 rpm.

5.0L Stock vs. Modified 302 Carb

Engine Specs-Modified 5.0L H.O. (Carb)
Displacement 306 ci
Bore 4.03
Stroke 3.00
Pistons Stock H.O.
Forged Yes and no—depends on year
Compression 9.2:1
Rods Stock H.O.
Forged No
Heads Dart Pro 1 210
Aluminum Yes
Iron No
Ported Yes (max flow 305 cfm)
Intake Valve 2.05-inch
Exhaust Valve 1.60-inch
Chamber Size 62cc
Intake Procomp Electronics dual-plane
Carb Holley 750 HP
Spacer No
Fuel System Aeromotive
Distributor Stock (MSD used on dyno)
Header (style) Hooker Super Comp long-tube
Header Size 13⁄4-inch
Cam Crane hyd-roller (hyd/solid-roller)
Intake Lift 0.542
Exhaust Lift 0.563
Int Dur Degrees 224 @ 0.050
Ex Dur Degrees 232 @ 0.050
LSA 112
Rockers Crane Gold roller
Ratio 1.6:1
Exhaust 2.5-inch with mufflers
Max Power Output (dyno) 401 hp @ 6,300 rpm
Max Torque Output (dyno) 370 lb-ft @ 4,000 rpm

Though wilder applications are obviously possible (we have exceeded 500 hp with a 302), this carbureted combination is typical of what can easily be accomplished with simple bolt-ons. Once again using the stock short-block, the 302 was upgraded with the Crane 224/232 cam, Dart Pro 1 210 heads, and a dual-plane intake. Typical of carbureted applications, the 302 produced slightly more peak power and less torque than the EFI version, with peaks of 401 hp and 370 lb-ft. The Dart heads were capable of supporting a great deal more power, but the limitation was the displacement, cam timing, and intake manifold. With a wilder roller cam, a single-plane intake, and a point or so more compression, 500 hp is a possibility, though with greatly diminished driveability. By contrast, either of the two 302 combinations listed here would be ideal daily drivers.

Photo Gallery

View Photo Gallery