Description
About This Engine
The Ford 428 Cobra Jet is one of the most historically significant performance V8 engines ever built. Introduced in April 1968 in direct response to the Chevrolet Camaro 396 dominating Mustang on drag strips, the 428 CJ was developed to restore Ford’s muscle car credibility. Ford achieved this by fitting the proven 428 block with larger-port cylinder heads borrowed from the 427 Low Riser, a high-flow intake manifold, and a 735 cfm Holley 4-barrel – all while keeping the engine manufacturable on a standard production line, unlike the expensive 427 it replaced.
Ford rated the 428 CJ at 335 horsepower – a figure widely understood to be conservative, partially strategic to keep insurance rates manageable for buyers. Independent dyno testing consistently showed output in the 400 to 410 hp range. When the Super Cobra Jet was introduced with LeMans-specification connecting rods and forged pistons plus an external oil cooler, even greater high-speed durability was achieved.
The 428 CJ powered the Mustang Mach 1, Shelby GT500, and countless race-prepped Torinos and Fairlanes. A compression-tested, variant-documented 428 CJ is the engine every serious Ford muscle car restoration revolves around.
Signs You Need a Replacement Engine
- Knocking under load – rod or main bearing wear on high-mileage FE engines
- Blue smoke under acceleration or on startup – worn valve seals on older FE heads
- Loss of compression on one or more cylinders – ring wear or scored cylinder walls
- Oil leaks at the front timing cover – a well-documented seep point on aged FE blocks
- Overheating – the FE 428 runs warm and high-mileage water jackets restrict coolant flow
- Oil consumption beyond 1 quart per 1,000 miles – ring or valve seal failure
Known Problems With This Engine
- External balance requirement: The 428 is externally balanced. The flexplate or flywheel and harmonic balancer must be specific to the 428. Using components from a 390 or other FE engine without rebalancing causes severe vibration and potential failure. We flag this before every order ships.
- Timing cover oil leaks: The FE timing cover gasket area is a chronic seep point on older engines. We inspect and report on all gasket surfaces.
- Valve guide wear on high-mileage FE heads: FE valve guides can wear significantly, causing oil burning at startup. We perform a valve cover inspection for oil burning indicators.
- CJ vs SCJ external identification: Both use the same block. The clearest SCJ identifier is the external oil cooler provision. Internally, LeMans capscrew rods and forged pistons distinguish the SCJ. We document this thoroughly before shipping.
Known 428 FE Variants
The 428 Cobra Jet (CJ, Q-code, 1968-1970) produced 335 hp at 10.6:1 with large-port 427-style heads and a Holley 735 cfm 4-bbl. The 428 Super Cobra Jet (SCJ, R-code, 1968-1970) kept all CJ specs plus LeMans capscrew rods, forged pistons, and an external oil cooler. The 428 Police Interceptor (PI, W-code, 1966-1971) used a longer-duration cam and higher-flow exhaust manifolds, rated 345 hp / 462 lb-ft for sustained high-speed running. The 428 Standard (1966-1970) was the original 428 with smaller ports, used in full-size Fords and Thunderbirds.
What Is Included
Included – Long Block: Block, crankshaft, pistons, connecting rods, camshaft, cylinder heads, valve train, oil pan, front cover, and water pump. Not Included: Intake manifold, carburetor, exhaust manifolds, distributor, ignition system, alternator, harmonic balancer, flexplate or flywheel. CRITICAL: The 428 is externally balanced. The harmonic balancer and flexplate or flywheel must be 428-specific. Do not use components from a 390 or other FE engine. No core charge.
Vehicle Compatibility – Direct Fit
The 428 Cobra Jet was factory installed in the Ford Mustang (Mach 1, GT500, Boss variants, 1968-1970), Ford Fairlane and Torino (1968-1970), Ford Galaxie 500 (1966-1970, PI and standard), Ford Thunderbird (1966-1971, PI), Mercury Cougar GT-E (1968-1970), Mercury Cyclone and Comet (1968-1970), and Mercury Montego (1969-1970). Compatible with any vehicle originally equipped with any FE engine (352, 360, 390, 406, 427, or 430).
Why Buy From Vaz Auto Solutions
- Variant confirmed before you pay – CJ, SCJ, or PI documented including casting number
- Compression tested across all 8 cylinders – results shared before order confirmed
- External balance requirement flagged before shipping
- Fitment verified for your specific Ford or Mercury vehicle
- No core charge – keep your old engine
- Free freight pallet delivery to all 50 states
- 15 day replacement warranty on internal engine defects
- Call (240) 301-0095 – speak with someone who understands FE engine variants
Gary S. –
Bought a 428 for my 1970 Ford Torino GT build. Vaz confirmed the external balance requirement and told me upfront I needed a 428-specific flexplate – which I sourced before the engine arrived. Engine compression was solid, timing cover had a small seep which they disclosed before shipping. Good experience overall.
Tom R. –
Finally found a documented 428 CJ for my 1969 Mustang Mach 1 project. Vaz pulled the casting number and confirmed the large-port heads before I paid a dollar. Compression came back 155 to 165 across all 8. Runs strong after install. These guys understand what a Ford muscle car restoration actually requires.