Mustang MonthlyHow To Engine
How-To ID A 289 High Performance Engine
We Look Inside Art Cairo's Pre-Production '64 1/2 289 High Performance To See What Made The High-Winding Small-Block So Special
Hi-Po MythsEver 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.
Myth 1: The 289 High Performance V-8 has forged pistons.
False: 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.
Myth 2: It has special connecting rods.
False: 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.
Myth 3: It has a dual-roller timing set.
False: 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.
Myth 4: It has larger valves and ports.
False: 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.
Myth 5: It has a special intake manifold.
False: Hate to burst your bubble, but the Hi-Po has the same 4V intake manifold as the 225-horse 289-4V engine.
Myth 6: It has a steel crankshaft.
False: 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.
Myth 7: The 289 Hi-Po has a deeper, high-capacity oil pan.
False: It's the same steel five-quart pan as the 289-2V/4V.
Myth 8: Some 289 High Performance V-8s were fitted with factory air conditioning.
False: The 289 High Performance V-8 was never available with factory-installed air conditioning.
Myth 9: Some 289 High Performance V-8s were fitted with the Thermactor California emissions system (air pump).
False: Not one of them was ever fitted with the Thermactor air-pump emissions system.
Myth 10: Some 289 Hi-Po blocks have screw-in freeze plugs.
False: None was ever factory equipped.