This story is not about a Ford 289 HiPo engine restoration. That ship sailed long ago when the factory ’65 short-block was used for a core charge during a rebuild in the ‘70s. It was an understandable move since no one could have predicted the value those original short-blocks would command today just because the VIN numbers were carved into the face of an iron block.
Here's the Mustang engine after some 30 years of storage. In the '90s, it was used for a magazine story on converting to a hydraulic cam and sported a Weiand aluminum intake, Holley 4010 carb, and MSD ignition. Lately, the Mustang was used for upgrade projects such as an Aeromotive in-tank fuel pump and Classic Radio swap that can play external MP3 sources.
Whipple Racing in Rapid City, South Dakota, removed the engine in addition to replacing the brake system. Note, a few cosmetic and equipment changes were made to the engine in the time that surpassed after it came out of storage. The engine was painted blue in the ’70s when it was rebuilt with a Ford remanufactured short-block. K-code engines in 1965 were painted black.
Rather, this article is about “reKreating” the 289 HiPo engine with modern parts while retaining as much of the K-code character as possible. The cost of restoring a 289 HiPo engine to Concours condition is too high, even if you can find NOS parts or surviving parts in good condition. Instead, this engine project will take advantage of new piston and camshaft technology along with upgrades developed for the lubrication, exhaust, and intake systems.
In the early days of the Mustang, the K-code was the only performance option — unless you spent a couple-thou extra for a Shelby GT 350 — which sported a modified 289 HiPo engine. The K-code engine was rated at 271 horsepower at 6,000 rpm with 312 lb-ft peak torque at 3,400 rpm. It was available from 1964 through 1967, and some 13,000 K-code Mustangs were built. This accounted for less than one percent of the 1.8 million Mustangs produced in that time span.
Here are some of the modern upgrades planned for this build, from left: The K-code has 3/8-inch rod bolts, but CNC Motorsports didn't feel there was enough metal in the stock rod to drill out the bolt holes. So, ARP Pro Series 5/16-inch Wave-Loc rod bolts were used. JE Pistons supplied a set of SRP flat-top pistons with coated skirts and a thinner ring package. The new pistons also weigh 100 grams less than the stock models. The stock rocker arms were quite tired, so a new set of COMP Cams Magnum roller-tip rocker arms were substituted. Finally, an ATI Super Damper was constructed to mimic the distinctive K-code balancer.
The original cylinder heads stayed with the engine through its lifetime. After a thorough cleaning, the heads received new bronze guides, new valve seats, and a valve job. Also, new Ferrea stainless-steel valves were installed. The combustion chambers measured out to 53.6cc with the dished valves.
The K-code engine is easily identified from the other 289 engines when peering under the hood. It features a 2-inch-wide damper, compared to 1-inch-wide damper found on standard 289s. The K-code engine also has a centrifugal-advanced dual-point distributor, whereas standard 289 engines had a vacuum-advanced single-point distributor.
Some of the machine work at CNC Motorsports included balancing the rotating assembly with the flywheel and new ATI damper, torque-plate honing the block, and surfacing the cylinder heads.
Perhaps the most iconic difference is heard and not seen; the solid-lifter camshaft that boasted specs of .460-inch total valve lift with 1.6:1 rockers and 310-degrees advertised duration. Ford also equipped the HiPo cylinder heads with threaded rocker studs and provided a slightly larger Autolite 480-cfm, 4-barrel carburetor with the K-code option.
Clearances were double checked. The mains came out between .0022- and .0025-inch, while the rods measure .0019- to .0021-inch. The pistons measured 4.038 inches on the coating inside the 4.040-inch bore.
This particular Mustang (and engine) has been in storage most of its life after the Ford remanufactured short block was mated to the original cylinder heads in the ‘70s rebuild. The car was used for a few tech articles which appeared in the old Petersen Publishing’s Mustang Monthly magazine. Most recently, it was used for recent web stories covering the installation of a new radio, another carburetor and ignition swap, new fuel tank, and significant front and rear suspension upgrades.
Constant overheating and an annoying internal knock prompted a decision to remove and disassemble the engine. Then a plan was developed to reKreate the K-code engine honoring as much of the original character as possible while using modern performance parts.
The 2.870-inch-stroke 289 crankshaft was already ground .010/.010, so only needed polishing before being installed in the MAHLE/Clevite bearings. Thrust clearance measured .005-inch, and the mains were torqued to 70 ft-lbs. Total engine displacement with the 4.040-inch bore and 2.870-inch stroke crankshaft is now 294.32ci.
CNC Motorsports in Brookings, South Dakota, disassembled the engine and took care of the considerable machine work needed to ensure the 55-year-old cylinder heads, block, crank, and rods from the ‘60s were stout enough to support modern power parts. Here’s a quick rundown of the machine work:
Crankshaft: Magnaflux, polish, balance w/ damper, and flywheel.
Connecting rods: Magnaflux, resize both ends.
Cylinder heads: Magnaflux, wash, machine spring pads, new seats, install bronze valve guides, surface deck, valve job.
The little ends of Ford rods were honed out to convert the pistons to free-floating. This move required drilling a small hole in the end for pin oiling. The rods were then fit to the SRP pistons from JE.
The heads were assembled with Ferrea Competition Plus stainless-steel valves (1.780-inch intake, 1.450-inch exhaust), COMP Cams springs (125 lb seat, 285 lb open), ARP 3/8-inch rocker studs and COMP Cams Magnum 1.6:1 roller-tip rocker arms. These Ferrea valves were not only stronger than a stock replacement but four- to five-grams lighter. They came with a standard 45-degree seat angle.
Ring gaps were set at .018-inch for the top compression ring and .020-inch for the second ring. Note the skirt coating and the limited skirt contact area to reduce friction over the full-round stock units. Also, stock ring sizes were 5/64-, 5/64-, and 3/16-inch. The new SRP rings are thinner at 1.2, 1.5, and 3.0mm.
The crankshaft that came in the Ford remanufactured short block from the ‘70s had already been turned .010/.010. There were no differences between the cast-iron crankshafts in all 289 engines, but HiPo cranks were carefully tested and selected for higher nodularity. HiPo engines also came with a thin, hatchet-shaped counterweight mounted next to the timing gear. This reman short-block didn’t have this counterweight. Since the SRP pistons from JE Pistons and ATI damper would all be new, rebalancing the entire assembly with the 20.4-pound flywheel was appropriate.
The block is wiped clean and coated with ATF before the pistons are installed. The rod caps are torqued to 30 ft-lbs, and side clearances were measured at .013- to .018-inch. Piston rock was also checked.
The connecting rods in a K-code engine are the same as standard 289 rods except that 3/8-inch bolts are used instead of 5/16-inch bolts. CNC Motorsports didn’t want to risk weakening the support structure around the bolt holes by drilling them out, so ARP Pro Series Wave-lok bolts were made from 8740-Chromoly steel with a yield strength of 200,000 psi. ARP main and head bolts were used in the engine assembly as were Clevite bearings from MAHLE Aftermarket and Driven Racing Oil assembly lube.
The lobes and bearing surfaces on the Nostalgia cam are coated with Driven assembly lube before the camshaft is installed in the block, followed by the COMP Cams timing set. Both the Nostalgia and Magnum 282S cams were degreed at this point to save time on the dyno. The Nostalgia cam came in at 107 degrees on a 108 centerline, while the 282S checked in right on the money at 106 degrees.
One of the biggest performance gains using modern parts was the piston selection. The original pistons were massive at over 580 grams while the line of SRP pistons from JE tipped the scales at 483 grams. Besides having less surface area than the old pistons, the new pistons feature coated skirts and sport thinner rings — reducing the friction load considerably in the cylinder. Also, CNC Motorsports converted the piston pins to full floating — again, reducing friction in the rotating assembly. The pistons are constructed from 4032 aluminum.
The original timing cover is installed before the Milodon oil pump and pickup are installed. A lump of modeling clay is used to ensure the proper pickup-to-pan clearance.
The factory 289 HiPo engine had an 11.5:1 compression ratio when it was first introduced in the 1963 Fairlane. That slipped to 10.5:1 in 1965, but still too high for today’s pump gas with an iron head. So, the SRP pistons were made to deliver a 9.9:1 compression ratio.
Milodon manufactures a beautiful 5-quart replacement oil pan for the small-block Ford which features baffling for improved oil control around the pickup. A Milodon pump was also used in the buildup. The final modern upgrade for the long-block was a set of MAHLE MLS head gaskets. MLS, or multi-layer steel, has taken the industry by storm in the past decade, offering superior sealing over traditional composite gaskets. The embossments in the layers act as “springs” to fill in the gap should the head start to lift away from the block under severe cylinder pressure.
The Milodon 5-quart pan features an internal oil-control baffle and gold iridite finish. ARP hardware and a Milodon one-piece gasket secure the pan to the block.
Topping off the engine for the first-round dyno testing was the original cast-iron intake manifold and a Quick Fuel 450 cfm carburetor. The original HiPo carb was a 480 cfm Autolite model, but they’re rather hard to come by these days. The original dual-point distributor was planned for this build, but at the last minute, a hairline crack was discovered on the shaft. Dyno testing would be conducted with a house MSD setup, and another solution would be sought for the final installation in the vehicle.
MAHLE MLS head gaskets measuring .040-inch thick were chosen for this project to help improve durability. With the heads positioned in place, there's a closeup view of the ARP rocker studs and the COMP Cams valvesprings.
The ARP head bolts are lubricated and torqued to 70 ft-lbs.
For photo purposes, the engine was buttoned up with the original timing cover, a new Edelbrock K-code water pump, ATI damper, original exhaust manifolds, and original valve covers. All ’65 289 HiPo engines were painted black with the traditional blue coming the following year.
Wait! What about the camshaft, you ask?
Part II of this story will cover dyno testing, which includes an in-depth look at two camshafts from COMP Cams reflecting the original HiPo specs as well as the famed Le Mans camshaft. The first is the Nostalgia Plus with numbers very close to the original HiPo camshaft. Second is the Magnum 282S grind. Both the original and Le Mans cams were used in the engine in the ‘60s and early-‘70s when the car rolled up most of its mileage. It will be interesting to see how modern interpretations from COMP fare on the dyno.
The lifters receive a generous coating of lubricant before being installed, followed by the pushrods and COMP Cams Magnum rocker arms. CNC engine-builder John favors poly-locks over the standard adjusting nut. Finally, the original intake manifold is bolted in place.
Additional dyno testing includes upgrading to a new Edelbrock intake manifold similar to the iconic FB4 intake rebadged for the Shelby GT350 engine. Other upgrades will include a higher flowing Quick Fuel carburetor and a set of JBA shorty headers. You can find a link to the Part II dyno testing here.
Final touches include an ATI damper, Edelbrock water pump, and Quick Fuel 450 cfm carburetor. The rest of the engine is mocked up with the original exhaust manifolds, valve covers, dual-point distributor, and air cleaner for photo purposes only. The original plan was to dyno test this configuration to see how close it would come to the factory 271-horsepower rating. Unfortunately, a crack was discovered on the distributor shaft and the exhaust manifolds wouldn’t fit on the dyno stand. More on the dyno testing in Part II.