Ford rated its ‘65 289ci high performance V8, better known as the “HiPo” or “K-code” engine, at 271 horsepower at 6,000 rpm with peak torque of 312 lb-ft at 3,400 rpm. This updated K-code-inspired engine built in Part I should do better for a number of reasons – including less friction in the cylinders, higher flowing exhaust and much-improved valvetrain.

As described earlier, the longtime owner of a ‘65 K-code Mustang needed a new engine. He had components from the original 289 engine, including the cylinder heads, intake manifold, exhaust manifolds, distributor and timing cover. The original short-block was traded in as a core for a fresh Ford remanufactured short-block that was used for a rebuild in late ’70s. As part of a magazine tech story in the ‘80s, the solid-lifter cam was replaced with a hydraulic version, and an aluminum intake manifold was installed.

The dyno test strategy basically revolves around a camshaft comparison. Here are the four camshafts that are part of this particular K-code’s engine’s character and driving the new camshaft decisions. On the bottom is the engine’s original factory camshaft. Next up is the Comp Cams Nostalgia cam designed to replace the factory HiPo camshaft. Then there’s the famed Le Mans camshaft that was in the engine when the current owner purchased the Mustang in 1972. On top is the Comp Cams Magnum 282S, which many forums and Mustang enthusiasts consider a practical replacement for the Le Mans cam.

Here’s how you can identify the original 289 hipo and the Ford Le Mans camshafts. An inverted “A” and an “E” were stamped into the core just behind the rear journal on the hipo cam. The part number for the Le Mans cam was stamped on the front journal.

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Restoring the engine to concours condition would have been expensive and time consuming—so the owner chose to “reKreate” the K-code engine with modern performance parts while maintaining much of the 289 HiPo character. He then added a couple more touches that were similar to the K-codes modified for the Shelby GT350 line.

Here’s the Nostalgia Plus cam lubed up and ready for installation during the engine build. Both the Nostalgia and 282S cams were degreed during assembly to save time on the dyno.

CNC Motorsports in Brookings, South Dakota, handled all the machine work and assembly. The block was bored out .040-inch over for a set of SRP pistons from JE Pistons. A good portion of the performance gains can be attributed to these pistons because they’re lighter, have less surface area on the skirts and feature thinner rings than the original pistons.

Before firing, the crankcase was treated to five quarts of BR40 break-in oil from Driven Racing Oil. Note that the Cobra valve covers were bead-blasted to a Shelby style appearance. For the first round of testing, the original iron intake manifold and a Quick Fuel 450 cfm carburetor were used along with an MSD ignition system.

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The original cast-iron exhaust manifolds, which are unique to the K-code due to their higher flowing design, would not fit on the dyno stand. So an A-B test with the JBA shorty headers could not be performed. The JBA headers are ceramic-coated stainless steel and feature 1 5/8-inch primary tubes that lead into a patented merge collector.

The engine was broken in using a shop carburetor for safety reasons. After the break-in, the valve lash was checked and the oil filter was cut open for inspection. Dyno operator Ryan Hedge always puts a magnet on the outside of the filter can to draw away harmful metal debris. He said this pattern was normal for a break-in with a solid lifter camshaft.

The full rotating assembly, including a new ATI damper and a resurfaced flywheel, was balanced, then the short-block was assembled with ARP fasteners, Clevite bearings, Milodon oil pump and 5-quart pan. The original heads were treated to bronze valve guides, new seats and a 45-degree valve job, then assembled with Ferrea stainless-steel valves, Comp Cams valvesprings, and Comp Cams Magnum roller-tip 1.6:1 rocker arms. Final engine assembly included MAHLE MLS head gaskets, the original intake manifold and a Quick Fuel HR-450 carburetor.

Camshaft Selection

The driving force behind two days of dyno testing was to compare two Comp Cams camshafts that reflect the original HiPo cam and the famed Le Mans cam that Ford offered through the Muscle Part catalog in the ‘60s (PN C7FE 6250-A). When the current owner purchased the K-code Mustang in ’72, the Le Mans cam was in the engine.

The Quick Fuel 450 was installed and timing checked at 35 degrees of timing for the first full pull. The dyno showed the engine running rich, but the shop couldn’t find jets to lean out such a small carb.

Ideally, the dyno testing would have been conducted with the two vintage bumpsticks in keeping with the goal of preserving the K-code engine character. In fact, the Le Mans cam was sent to Comp Cams for analysis on its Adcole 911 gage. According to the manufacturer specs, the Le Mans cam had a lobe lift of .330-inch for both intake and exhaust. The Adcole report said the lobe lift on the intake side ranged from .307-inch to .321-inch while the exhaust side ranged from .312-inch to .324-inch. The original specs also indicate 216 degrees duration at .100-inch lift. The Adcole report indicated a range of 214.8 to 216.5 degrees across all 16 lobes. It’s safe to assume that manufacturing variables and wear over the years has led to inconsistency in the original cams, so let’s see what’s available that closely matches those legendary cam profiles.

The next full pull was a straight A-B test between the stock iron intake manifold and an Edelbrock Performer RPM. This change alone picked up 23 horsepower.

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Now for the lengthy teardown to change cams. The distributor and intake system were removed followed by loosening all the rocker arms and removing the pushrods and lifters. The shop kept the lifters in order of the lobes should that cam be returned to the engine. Other necessary chores included removing the ATI damper with the proper tool and pulling the Edelbrock water pump.

Off came the timing cover and timing set followed by the removal of the Comp Nostalgia camshaft.

The original 289 HiPo cam (PN C30Z-6250-C) had 310 degrees advertised duration (194 degrees at .100-inch lift) with a .460-inch total lift at the valve and lobe separation angle of 114 degrees. The problem with comparing modern cams with those from the ’60s is that SAE hadn’t implemented the standard .006-inch valve-lift spec for advertised duration, and Ford didn’t list duration at .050-inch lift, which is today’s most-used comparison tool.

According to Billy Godbold of Comp Cams, however, the velocity limit of the Ford .875-inch tappet means that the .050-inch lift should be 30 to 40 degrees more than the .100-inch lift listed by Ford for its performance cams in the ’60s.

“The 194 at .100 is more in the 224-234 at .050 range,” estimates Godbold.

By comparison, the Comp Cams Nostalgia Plus 271S cam is designed to replicate the original HiPo camshaft “character” with a more aggressive, dual-pattern lobe design. This cam has a lobe separation of 112 degrees and gross valve lift of .495-inch intake and .490-inch exhaust. Duration at .050-inch is 225 intake and 232 exhaust-so it’s very close to the original HiPo cam.

Teamed with Comp Cams lifters and .080-wall, 5/16-inch-diameter chromoly pushrods, the Nostalgia Plus cam was broken in using BR40 Driven Racing Oil. This 10W-40 oil has a proper zinc and phosphorus formula to protect flat-tappet camshafts. The oil is also suitable for a full day of dyno testing after break-in, which comprised 30 minutes on the dyno under various RPM and loads. The break-in setup also included a shop carb and ignition system—both were known factors to ensure a safe startup.

The CNC shop then installed the Comp Cams Magnum 282S, which closely resembles the specs designed for the famed Le Mans camshaft used in the early GT40 cars equipped with 289 engines. Wonder what those 180-degree headers did for power in those days?

Following the break-in procedure, the valve lash was rechecked at .012-inch and the oil filter removed for inspection. The original dyno game plan was to use the factory HiPo dual-point distributor, however, a crack was discovered in the shaft just before installation. So the shop’s MSD system remained for dyno testing. Timing was set at 35 degrees total advance. The shop carb was then swapped out with the Quick Fuel HR-450, which is close to the 480 cfm Autolite found on the 289 HiPo engine. The original plan also called for the factory exhaust manifolds on the baseline test, however, they wouldn’t fit on the dyno stand. A set of JBA Performance Exhaust shorty headers that will be used when the engine is installed in the ’65 Mustang was bolted on for the dyno runs.

The Results

As expected, the small-block Ford—now displacing a total of 294.32 cubic inches—performed better than the original 289 HiPo with a final pull of 308.1 horsepower at 6,000 rpm. Peak torque was 323 lb-ft at 3,500 rpm. The shop probably could have pulled a little more from the engine, since the engine was running rather rich at around 11.5:1 AFR. However, no one in a race shop that works with high-horsepower combinations could find jets small enough to lean out such a small carb.

With the 282S cam installed, the valve lash was set at .022-inch. Since dyno time was running tight, the shop installed the Quick Fuel 600 cfm carb at this time.

Once again, the engine was broken in using Driven BR40 break-in oil, then the filter was cut open and inspected.

The Quick Fuel HR-600 was set up with 66 primary jets and 72s in the secondary. Following a couple of test pulls, those were changed to 69 and 75, respectively.

The next test was a straight A-B comparison between the stock intake manifold and an Edelbrock Performer RPM intake. According to Edelbrock, this manifold is an evolution of the famed FB4 intake that was rebranded for the Shelby version of the ’65 Mustang. The GT350 started out as a K-code Mustang, and the engine was upgraded with the Shelby aluminum intake, a 715 cfm Holley carb and Tri-Y headers for a 306 horsepower rating at 6,000 rpm with peak torque of 329 lb-ft at 4,200 rpm.

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The intake swap alone produced a horsepower reading of 331.5 at 6,000 rpm with peak torque of 326.4 lb-ft at 4,100 rpm, so we’re well within the Shelby GT350 jurisdiction. Again, the AFR was very fat around 11.8:1. With the Edelbrock manifold, the peak torque didn’t improve that much but the torque curve moved upwards noticeably to help generate the added horsepower at higher RPM.

Here are the best pulls from each of the three setups.

The final dyno test involved swapping in a Comp Cams cam that resembles the Ford Le Mans camshaft. The Ford cam (PN C7FE-6250-A) sported specs of 318 degrees advertised duration on the intake (216 degrees at .100-inch lift) and 304 degrees advertised duration on the exhaust (216 degrees at .100-inch lift). Total valve lift was .510-inch, and the lobe separation angle was 108.5 degrees. Using Godbold’s estimates, this cam would be around 250-256 degrees duration at .050-inch lift.

The Comp Cams Magnum 282S comes with 235 degrees duration at .050-inch lift and gross valve lift of .528-inch. Lobe separation is 110 degrees. The cam was heavily coated with Driven assembly lube before installation. A fresh oil filter was spun on, and a fresh supply of Driven BR40 break-in oil was poured into the crankcase after the engine was buttoned up.

Since the dyno schedule was getting tight, a Quick Fuel HR-600 replaced the HR-450 to combine a couple of planned A-B tests. Following a couple pulls, the carb was re-jetted to achieve a 12.4:1 AFR. The result was a pull of 350.4 horsepower at 6,200 rpm with peak torque of 330.1 lb-ft at 4,800 rpm.

The K-Code Finds a Home

Back to Whipple Racing where the engine was installed along with new wiring in the engine bay. An electronic distributor and coil that resemble the early dual-point setup were found online. Before startup, the engine was treated to Driven HR5 10w-40 oil, which has a ZDDP additive package designed for solid-lifter cams. The 4-speed Toploader transmission was also inspected and refreshed with Driven 80w-90 GL-4 gear oil. Other long-overdue maintenance chores included balancing the driveshaft and replacing U-joints along with installing a new battery.

Mating up to the JBA shorty headers is a complete JBA dual exhaust with a high-flow H-pipe similar to the original K-code exhaust arrangement. This JBA systems is constructed from 2.5-inch mandrel-bent stainless steel tubes and fully welded mufflers that provide a powerful exhaust note that is well suited to the Mustang character. Finally a new set of American Racing 15x7 Torq Thrust rims and 215/60R-15 BFGoodrich Radial T/A tires from Tire Rack were lugged on.

Here is the updated ’65 K-code fastback with 350 horsepower under the hood.

It’s obvious the engine is handicapped by the unaltered cylinder heads as the power simply falls off the table at about 6,000 rpm. But it’s a great sounding engine with plenty of pep for cruising and shows. Remaining chores included installing the engine at Whipple Racing in Rapid City, South Dakota, replacing all the wiring forward of the firewall and installing a JBA 2.5-inch stainless-steel exhaust system. The final touch was bolting on a set of American Racing Torq-Thrust wheels and BFGoodrich Radial T/A tires.

And a final peek under the hood.

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