You’ve probably seen the above emblem on dozens of 1965-1966 Mustangs. Ford has sold 10 times as many of these emblems than they did real HI-PO engine equipped Mustangs. So what does this fender emblem really mean? It means that the car has the 271HP 289 HI-PO engine. The 5th digit of the VIN on a real HI-PO car must be a 'K', hence, the 'K-Code' Mustang.

HISTORY:

The K-code 289 271HP engine was developed by Ford in the early sixties and offered first as an option on the 1963 Ford Fairlane. In late 1964 and in 1965 the HI-PO engine became a Mustang production option*. There are a few so-called 64 1/2 HI-POs generator equipped (the distinguishing feature) Mustangs. The HI-PO engine was also offered as a production option 1966 and sadly for the last time in 1967. Because of the potential racing applications of the 271 HI-PO engine and to limit liability, Ford warranted the HI-PO engine for 90 days/4,000 miles. All other Mustang engines came with a standard 1 year/12,000 mile warranty.

* 271 HP Hi-Performance289 CID 4V (includes Special Handling Package and 6.95 x 14 dual Red Band tires. Source 1965 Mustang Illustrated Facts and Specifications Manual.

PRODUCTION STATISTICS:

1965 – 7,273 of the 680,989 of the Mustangs built (1.0%)
1966 – 5,469 of the 607,568 of the Mustangs built (0.9%)
1967 –    489 of the 472,121 of the Mustangs built (0.1%)

3 Year Total = 13,214 of the 1,760,678 Mustangs produced (.75% less than 1.0%)

TECHNICAL ASPECTS:

The engine begins life as a standard 289 Cubic Inch cast iron block. Unverified and an area of controversy is the crankshaft. It is said that the crankshafts were tested for hardness and ones that met a standard were handpicked for the HI-PO engine, the ones that didn’t went into standard 289 engines. The rod bearings and bolts were upsized. The front of the crankshaft has a hatchet weight to balance out the weight of the larger rod bearings and bolts. The harmonic balancer was also enlarged for the same reason. Pistons were cast and the compression ratio is 10:5 to 1. The alternator pulley was also enlarged to reduce the number of revolutions at high engine RPMs. HI-PO engines also had a metal radiator shroud, and a wide four blade, riveted cooling fan.

The cast iron heads were unique to the HI-PO engine, with chrome plated valve stems, solid valve lifters, screw in rocker studs, and cast in valve springs guides. The camshaft has special contoured lobes for high-lift valve openings, and contributes to the slightly uneven idle and that unique solid lifter sound. The exhaust manifolds were cast iron free flowing 'header type' and all HI-POs had a 2" exhaust system with a crossover design 'H' pipe to equalize pressure and dual parallel, low restriction mufflers.

The intake manifold was a standard cast iron 289 4V, but the carburetor was a 600 CFM Autolite 4100 with a manual choke with a tuned 360 degree low restriction air cleaner. The distributor was a Fomoco dual-point mechanical advance, ignition wires were solid core, and the spark plugs (in 1965) were Autolite BF-32s. The BF-32s were a fairly cold spark plug that occasionally fouled in normal driving and BF-42s (slightly hotter) spark plugs were specified for later 1966 & 1967 HI-POs.

A factory engine dress up kit was standard and included polished chrome valve covers and air cleaner.

The transmission is a Ford design close-ratio 4 speed cast iron top loader with 10.4" clutch that was a mandatory option with the 271 HI-PO engine option in 64 1/2 and 1965. In late 1966 and in 1967 an automatic transmission was an available option. The rear axle is the Ford famous 'unbreakable' 9” ring gear in ratios of 3:50, 3:89, and 4:11. Traction lock rears were available from 1966. Traction lock was not available in 64 1/2 or 1965 Mustangs.

A heavy duty suspension (front/rear springs & shocks) with a larger (13/16") front sway bar was included with the HI-PO engine option. This was the same 'Special Handling Package' offered in the V8 'GT' option cars. Tires were 14" dual redlines standard with a no cost option of black or whitewalls. The steering was the fast ratio box (16 to 1) used with the power steering cars, but without the power assist. No power steering, power brakes, or air conditioning was available from the factory on the K-Code HI-PO.

SUMMARY:

The K-code cars are an absolute blast to drive. With a 6,500 rpm redline (7,000 if you’re feeling lucky), a close ratio 4 speed, and a 3:89 rear axle, high 14 second 1/4 mile times were possible. The car just explodes from about 3,500 rpms (when the vacuum secondaries open) to the redline and the engine/exhaust sounds incredible. Click to hear Mario shifting his HI-Po four speed manual transmission.

Click here to view a multi-page article on the 1965 HI-PO Mustang that appeared in the September 1964 issue of Car Life Magazine.

1965 Rangoon Red HI-PO VIN 5R07K256987 owned by Mario Messina of West Chester Pa.

First Place finish, AACA Spring Eastern National, Virginia Beach, VA May 11-13th 2006

Senior First Place, AACA Fall Eastern National, Hershey, Pa October 05-08th 2006

THE SOURCE:

If all this information has whetted your appetite for a real High Performance Mustang the best place to visit is www.hipomustang.com. This is 'THE SITE' for K-code freaks and the denizens of this site are hardcore knowledgeable HI-PO Mustangers. Sold through this site is the best book, the bible of K-code information; The High Performance Mustang by Tony Gregory. This book gives you all you need to know about identifying real K-codes and includes a K-code registry. You can also verify VIN codes on the website.

RECOGNITION:

MCCM wishes to publicly thank Mario for his invaluable contributions to the content of this HI-PO web page, and for sharing his knowledge and his beautiful Show Winning Red 1965 Mustang K code HI-PO Hardtop. All photos are the property of and courtesy of Mario Messina. You can contact Mario Messina directly at lumpoire@aol.com.

Thanks for visiting you are guest number ?, and continue to look to the MCCM web site www.midcomustang.com to provide relative information dedicated to the preservation, care, history and enjoyment of vintage model Ford Mustangs.