For 43 years, the 289 High Performance small-block has been more myth than fact. It probably gets more credit with enthusiasts than it deserves due to rarity more than anything. What makes it "high-performance" isn't unusual or rare. What Ford did to the 289 isn't any more out of the ordinary than good, old-fashioned, hot-rodding trickery.
The 289 High Performance is a warmed-up 289 with a hotter solid-lifter camshaft, cylinder heads and a dual-point ignition designed for higher revs, cast-iron header exhaust manifolds, and a wider harmonic balancer.
So what's the big deal? Not much, unless you're restoring a K-engine-code '65-'67 Mustang or are interested in building an authentic 289 Hi-Po small-block for your non-K-code Mustang. What makes the Hi-Po a big deal is authenticity when building a K-code Mustang with the real thing between the shock towers.
We're going to teach you the basics of the 289 High Performance with quick facts you can use in your engine building and Mustang spotting. Based on what we know about the Hi-Po, you can build a homegrown Hi-Po engine without spending a fortune in elusive castings and pieces. You can achieve the clatter of 16 mechanical tappets and the throaty tailpipe sound with the right camshaft and exhaust tuning. And, you can generate more horsepower and torque without suffering with driveability issues.
From the factory, the '65-'67...
From the factory, the '65-'67 Mustang's 289 High Performance was equipped with chrome valve covers and an open-element air-filter assembly.
Although the 289 High Performance block has a unique part number, it was not a unique block. The only difference was its wider main bearing caps. According to the 289 High Performance Mustang book by Tony Gregory, the 289 2V and 4V engines have 151/416-inch main caps that taper to 51/48 inch at the top. The Hi-Po caps are 151/416 inch from top to bottom.
This is a 289 High Performance...
This is a 289 High Performance block plucked from the engine bay of 5F07K100148-a one-off '6411/42 Mustang hardtop built for Henry Ford II.
The car is one of approximately...
The car is one of approximately 180 pre-production Mustang units built prior to the official March 9, 1964 startup date. The Hi-Po block really isn't unique. When you subtract the main caps, it's just another 289 block.
Some, but not all, early 289 High Performance blocks had screw-in oil gallery plugs. Despite urban legend, 289 High Performance blocks never had screw-in freeze plugs either. Those were reserved for the '69-'70 Boss 302 blocks only.
Factory-installed 289 High Performance engines had the vehicle serial number stamped into the righthand side of the block near the battery's negative-cable attachment point.
Here again is where fact blows fiction right out of the water. Ford never built a production 289 High Performance V-8 with a steel crankshaft. The Hi-Po has the same 1M cast-iron crankshaft as the 289-2V/4V engine. However, Hi-Po cranks were handpicked and Brinnel-tested for strength.
During assembly of this historic...
During assembly of this historic Hi-Po, we get to see the 289 High Performance main caps, which are wider than the 2V/4V caps. These guys are 151/416-inch from top to bottom. Mexican small-block castings also had the wider 151/416-inch main caps.
The 289 High Performance was fitted with the same basic C3AE connecting-rod forgings as the 2V/4V engines. Where they differ is the larger 31/48-inch bolts, compared to 51/416-inch bolts in the standard engines. This is a cool modification you can do on any 289 or 302 connecting rod to improve strength. The downside is, there is less steel around the 31/48-inch bolts, which weakens the rod to some degree. The best compromise is 51/416-inch ARP bolts, which are stronger and don't affect rod strength.
The 289 High Performance bottom...
The 289 High Performance bottom end isn't much different from what we find in 2V/4V engines. It has the same 1M cast-iron crankshaft and C3AE connecting-rod forgings. Pistons were cast from the factory, and most rebuilds use forged. If you're nervous about the cast crank, relax. Carroll Shelby went racing with this crankshaft and spanked Corvettes in the process.
Production 289 High Performance engines were fitted with cast pistons that were good for 6,000 rpm. Forty years ago, forged pistons weren't all that common, and they certainly weren't conventional in production engines due to cost and technology. At the time, forged pistons were available from the aftermarket.
This is a standard 289-2V/4V...
This is a standard 289-2V/4V C3AE connecting rod with 5/16-inch bolts. The only difference between this rod and a Hi-Po rod is bolt size. It's exactly the same forging. The '69-'70 Boss 302 uses this same forging with 3/8-inch bolts. Displacement comes from using a different crank in the Boss 302 with a 3-inch stroke.
Although most of the Hi-Po bottom end is shared with the 2V/4V engines, two items aren't: the harmonic balancer and slide-on counterweight. They're there for an important purpose: balance. The 289 Hi-Po has 3/8-inch connecting-rod bolts, which adds weight to the reciprocating mass (piston and rod assembly). This called for a wider harmonic balancer and the added counterweighting from the slide-on counterweight.
The 289 High Performance V-8's personality comes from an aggressive mechanical flat-tappet camshaft that does its best work at high revs. Peak horsepower and torque come in around 6,000 rpm. For a flat-tappet camshaft you can use on the street, the C3OZ-6250-C factory bumpstick is aggressive, with .460/.460-inch valve lift and 310/310-degrees of duration. Lift at the lobe is .298/.298 inch. Raw torque and horsepower come on strong in the high revs.
All small-block Fords of the period were fitted with Carter fuel pumps. From 1964 to 1965, it was a screw-together Carter pump with the fuel filter. From 1966 to 1967, Ford used a sealed Carter pump without the filter canister. The Hi-Po engine differs in volume: It delivers more fuel than its 2V/4V counterparts.
A close look at 5F07K100148's...
A close look at 5F07K100148's block casting information reveals its pre-production status, with a cast date code of 3H20: August 20, 1964. The casting number of C40E-6015-C confirms its status as a 1964 block casting. Some Hi-Po blocks were marked with an HP, according to Tony Gregory's book.
Clutch & Flywheel
As you might expect, the Hi-Po employed more heavy-duty driveline components. Manual transmission applications had two basic types of Borg & Beck, three-finger clutches that measured 10.4 inches in diameter. Much of it had to do with spring pressure. Because early Hi-Pos struggled with clutch slippage under hard acceleration, Ford went to a stiffer clutch for 1967.
Classic Mustangs have always suffered with clutch-release bearing and linkage woes because the old-fashioned three-finger clutch yields great pressure on the release bearing and linkage. No matter what you do with the bellcrank clutch linkage, it will not stand up well to Borg & Beck clutch stress. You can count on failure at some point in clutch service life.
Today, the Hi-Po solution is the installation of a Centerforce Dual-Friction clutch and flywheel package to improve driveability and performance. The Centerforce clutch offers light clutch-pedal effort because it's a diaphragm-style. It gets even better with the flyweights on the diaphragm fingers. As engine revs increase, the flyweights place more pressure on the fingers and disc, eliminating slippage. This is a terrific design that offers the best of all worlds.
These are C3AE rod forgings...
These are C3AE rod forgings without their bolts. Ford machined out the holes to 31/48 inch to accommodate the larger 31/48-inch rod bolts for the Hi-Po and later Boss 302. On the left is an early rod forging with an oil hole to lube the cylinder walls. On the right is a forging without the oil hole.
Our greatest fascination with the 289 Hi-Po is likely its unique cylinder heads. Urban legend has always given the Hi-Po head larger ports and valves than other small-block Fords, which has never been true. Valvespring pockets for stability and screw-in rocker-arm studs for dependability make the Hi-Po head unique, because the more common press-in studs tend to pull out with aggressive camshafts and high revs. Outside of these factory modifications, the Hi-Po heads are virtually the same as the 2V/4V heads. Spotting a 19, 20, or 21 cavity number in the corners of the castings outside of the valve-cover areas on the exhaust side quickly identifies Hi-Po heads.
Art Cairo's factory experimental...
Art Cairo's factory experimental Hi-Po had cast pistons originally. We're fitting it with Federal-Mogul Speed-Pro forged pistons for durability. Rods have been reconditioned and fitted with new ARP 31/48-inch bolts. These piston skirts are Teflon-coated to reduce friction.
Enter text here.These heads were fitted with stiffer valvesprings for obvious reasons: to reliably slap the valves closed at high revs. Spring pressure was approximately 350 pounds on the Hi-Po heads. Smaller damper springs were also used.
Look for casting numbers C3OE, C4OE-B, C5OE-A, C5AE-E, C7ZE (service head), and C8ZE-B (also a service head). The C8ZE-B service head does not have the two-digit cavity number mentioned earlier.
What If Your Hi-Po Block Is Toast?
What happens if you're restoring a K-code Mustang and have a block that's .040-inch over or damaged from engine failure? You have two options: have the block sleeved at approximately $100 a cylinder or search for a C4OE or C5AE block casting with a standard bore (challenging to find today) and transfer your Hi-Po main caps to the fresh block. To use the Hi-Po main caps on the fresh block, have the block and caps line-bored and honed for a perfect match. Mexican Ford blocks also have the wider Hi-Po-style main caps if you need wider main caps. Mexican blocks can be identified by an M in the fourth position in the casting number.
Because 289 High Performance blocks were stamped with the vehicle serial number, you'll need to stamp this number into the replacement block using the same type Ford used.
This is the garden-variety...
This is the garden-variety 289-2V/4V harmonic balancer-narrow, just shy of an inch in width and 631/48 inches in diameter.
The 289 High Performance balancer...
The 289 High Performance balancer is considerably wider at 311/464 inches. It's also larger at 611/42 inches in diameter. The wider, larger balancer helps damp vibration. It works hand-in-hand with a steel counterweight behind the timing set to offset the added weight of larger 31/48-inch rod bolts.
This is the exact replacement...
This is the exact replacement from Crane for the original Hi-Po camshaft. It's a good, old-fashioned solid-lifter camshaft that has to be broken in properly when the engine is first fired. Run at 2,500 rpm for 30 minutes, then shut it down and change the oil. The valve lash is .018 inch for both intake and exhaust in 1965-'66. For 1967, it's .019-inch intake and .021-inch exhaust.
Originally, the 289 High Performance...
Originally, the 289 High Performance had a narrower timing set to accommodate the slide-on counterweight. Here, the engine has been dynamically balanced without the counterweight, which makes it unnecessary. The dual-roller timing set slides right into place without concern for the counterweight.
Fresh fasteners are important...
Fresh fasteners are important to a Hi-Po or any engine build because each time one is torqued and loosened, it's weakened to some degree. Lubricating the bolt holes and threads prior to tightening reduces the stress. Fresh hardware also looks nicer.
The 289 Hi-Po was factory-fitted...
The 289 Hi-Po was factory-fitted with a high-flow fuel pump. Two basic types were used between 1964 and 1967. From 1964 to 1965, Ford used a Carter screw-together pump (C5OZ-A) with the fuel-filter canister. For 1966 to 1967, a sealed Carter pump was used (C6ZZ-A) without the canister fuel filter.
Because the 289 Hi-Po is a high-revving engine, good coil saturation and a reliable spark were required. This is why the Hi-Po was equipped from the factory with a dual-point ignition. Not only does the Hi-Po distributor have dual breaker points, they aren't the same points found in single-point distributors. They're Autolite dual-point specific, with stiffer breaker arms for smoother operation at high revs. What makes the Autolite dual-point even more unique is the absence of a vacuum advance unit. Only a centrifugal advance is involved, which comes on as engine revs increase.
Six Hi-Po distributor part numbers were involved from 1963 to 1967: C3OF-D, C3OF-F, C4ZF-D, C5OF-E, C7ZF-J, and C7OF-K. All employ the same basic advance curve and breaker dwell settings. Ford opted for cooler-heat-range spark plugs for the Hi-Po. Where the 289-2V/4V had the Autolite BF42, the Hi-Po had BF-32s.
The 289-4V engines were fitted with a 480-cfm 4100 carburetor with an automatic choke; the Hi-Po got a 600-cfm carburetor with a manual choke. Carburetor identification is simple: just look at the bore sizing and the carburetor tag (if equipped). The 480-cfm Autolite 4100 has 1.08 venturis and 171/416-inch bores. The larger 600-cfm 4100 has 1.12-inch venturis with 191/416-inch bores. What makes the Hi-Po's 600-cfm 4100 unique is the absence of a hot-idle compensator and an automatic choke. These items were common with big-block applications.
There are eight different Ford part numbers for 289 Hi-Po carburetors. Five were for manual transmissions (no kick-down linkage). Two were for automatic-transmission applications. They became more specific mostly in jet sizing, which hinged on where they were delivered new. High-elevation deliveries received different jetting than low-elevation.
The 289 Hi-Po alternator ('65-'67) and generator ('6411/42 only) have a larger drive pulley to keep the revs down at high revs. This keeps the alternator/generator windings from exploding at high revs. Art Cairo's unusual '6411/42 hardtop, which was used for our photography, was fitted with an early Lincoln-style Autolite 35-amp alternator, which is likely the only '6411/42 ever assembled with an alternator charging system.
Another obvious difference with the 289 Hi-Po is the factory cast-iron exhaust headers. Designed to improve exhaust scavenging, much like the late-model 5.0L High Output Mustangs did with shorty tubular headers, the cast-iron headers don't claim to work as well as long-tube aftermarket headers. But, it's better than the standard 289-2V/4V log-style exhaust manifolds. The part numbers are C3OE-9431-B (driver side, '64-'65), C4ZE-9430-A (passenger side, '64-'65), C7ZE-9431-A (driver side, '67 only), and C7ZE-9430-A (passenger side, '67 only).
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.
Oiling System Security
The 289 High Performance engine was fitted with the same type of oil pump, pickup, and pan found with the 2V/4V engines. When you rebuild the Hi-Po, opt for a high-volume oil pump for improved lubrication at high revs. Install a new pickup as well.
Although it is rumored all 289 High Performance engines had screw-in oil-gallery plugs, not all of them did. When you find press-in plugs, replace them with screw-in plugs when the block is being machined. Make sure your machine shop does a thorough job of cleaning the block and all of the passages afterward.
When you rebuild, use a high-volume...
When you rebuild, use a high-volume oil pump and a new pickup screen. Make sure the crankshaft counterweights clear the oil pump by at least .050 inch.
Oil-gallery passages at the...
Oil-gallery passages at the front of the block behind the timing set should receive screw-in plugs for safety. Do this during the machining process and make sure all passages are hospital clean.
This is the distinctive 289...
This is the distinctive 289 High Performance cast-iron exhaust header, which looks more like a shorty header than an exhaust manifold. This manifold is similar to the '69-'70 351W exhaust manifold.
Two Great Hi-Po Books
We recommend two terrific sources for 289 High Performance engine information. Mustang & Ford Small-Block V8-1962-'69 by Robert Mannel, published by RPM Press, is the best book we've ever seen on the small-block Ford. We're talking hundreds of pages of photos, text, and details on all '62-'69 221/260/289/302/351W small-block V-8s, including the '63-'67 289 High Performance. For more information, contact RPM Press, Dept. MM, 340 Clicktown Rd., Church Hill, TN 37642; e-mail firstname.lastname@example.org.
Another good book is The 289 High Performance Mustang by Tony Gregory, available from Marv's Mustangs, Dept. MM, 12600 Leatherwood Ct., Raleigh, NC 27613; 919/848-6786; www.hipomustang.com. It has plenty of information related to 289 High Performance Mustangs. Register your '65-'67 289 High Performance Mustang while you're at it.
This cylinder head looks different...
This cylinder head looks different because it's a factory experimental casting used on the 5F07K100148 car.
Both cylinder heads have this...
Both cylinder heads have this XE-118715 casting number, indicating experimental engine pieces. Chamber, valve, and port sizes were the same as every other Hi-Po casting we've seen.
We discovered these stampings...
We discovered these stampings (experimental tracking numbers) in the end of each cylinder head.
The unique nature of the Hi-Po...
The unique nature of the Hi-Po head is apparent here: valvespring stability pockets and screw-in rocker-arm studs. This is testimony to the durability of those cast-iron rocker arms. The high-revving Hi-Po was fitted with them from 1963 to 1967. Rail-style rocker arms used from May 8, 1966 forward were common only to the 2V and 4V engines.
This is the Autolite dual-point...
This is the Autolite dual-point distributor. There were two basic versions: the early one with an oiling port and the version shown here without one. Early versions were used in 1963-1964, stamped with C3OF and C4ZF part numbers. None was ever fitted with a vacuum advance.
We found this Autolite 4100...
We found this Autolite 4100 on top of Art's Hi-Po engine. It has the hot-idle compensator, which makes it incorrect for a Hi-Po application. It does, however, have the manual choke. It also has the larger 1.12-inch venturis and 191/416-inch throttle bores, making it 600 cfm. From a correctness standpoint, it isn't the right carburetor for a Hi-Po.
Here's the larger Hi-Po alternator...
Here's the larger Hi-Po alternator pulley at 371/48 inches. It also takes a longer belt. Generators had a 4.32-inch-diameter pulley.