Ever since the 289 High Performance V-8 was introduced in the '63 Fairlane, urban legend has abounded with this engine. Let's look at those myths and set the record straight.
The 289 High Performance V-8 has forged pistons.
From the factory, the 289 Hi-Po had the same C3OZ-6108-L cast flat-top pistons found in the 225-horse 289-4V engine. Performance improvement kits were available from Ford and the aftermarket with better pistons.
It has special connecting rods.
It has the same C3AE forging as the 289-2V/4V engines. However, this forging in the Hi-Po is fitted with larger 31/48-inch rod bolts, not 51/416-inch bolts found in the 289-2V/4V engines. The rod is machined to make way for the larger bolt head and shank.
It has a dual-roller timing set.
It has a standard timing set that's narrower than the timing set in stock 289-2V/4V engines. It's narrower to make way for the slide-on counterweight that goes on the crank first.
It has larger valves and ports.
The 289 High Performance head has exactly the same size valves and ports as the 289-2V/4V head castings. Not even the '67 service head, once rumored to have larger ports, is any different.
It has a special intake manifold.
Hate to burst your bubble, but the Hi-Po has the same 4V intake manifold as the 225-horse 289-4V engine.
It has a steel crankshaft.
Not a single 289 High Performance V-8 was ever equipped from the factory with a steel crankshaft. The only Ford small-block ever factory-fitted with a steel crank was the '69-'70 Boss 302. The Hi-Po has a 1M cast crank just like the 2V/4V engines.
The 289 Hi-Po has a deeper, high-capacity oil pan.
It's the same steel five-quart pan as the 289-2V/4V.
Some 289 High Performance V-8s were fitted with factory air conditioning.
The 289 High Performance V-8 was never available with factory-installed air conditioning.
Some 289 High Performance V-8s were fitted with the Thermactor California emissions system (air pump).
Not one of them was ever fitted with the Thermactor air-pump emissions system.
Some 289 Hi-Po blocks have screw-in freeze plugs.
None was ever factory equipped.
Art Cairo's 289 Hi-Po gets...
Art Cairo's 289 Hi-Po gets a new Centerforce Dual-Friction clutch and flywheel.
This enables him to keep the...
This enables him to keep the correct factory clutch linkage without a lot of pedal effort.
This is a typical pair of...
This is a typical pair of 289 High Performance heads fresh from machine work. As you can see, they have the 49.2cc chambers fitted with 1.78/1.45-inch intake/exhaust valve sizing, which makes them virtually identical to the 2V/4V head. Early Hi-Po heads (meaning 1963 for the Fairlane) had 1.67/1.45 valve sizes.
Intake-valve sizing changed...
Intake-valve sizing changed to 1.78 inches in mid-1964. If you're redoing a set of Hi-Po heads, you can step up to 1.94/1.60-inch valve sizing and gain some ponies.