1966 Mustang Engine Information – 289 cubic inch V-8 (4.7 L Windsor V8)

The 289 Windsor V8

This is Ford’s V8 90 degree overhead valve engine that everyone wanted in the first few Mustang years. It was dependable, economical to maintain, had adequate power and was easily modified.

In 1965 through 1966, you could get the 289 in either a 2 barrel or four barrel version. If you wanted the two barrel setup, you received an Autolite 2100 equipped with an automatic choke. If you wanted the “D” coded car in 1964 & 1965 you received an Autolite 4100 (4V) equipped with an automatic choke. If Your car had the “A” code, from 1965 – 1967 the engine was equipped with an Autolite 4100 (4V – 1965-66) and in 1967 it received an Autolite 4300-A (4V) square bore base with an automatic choke. For those power hungry individuals that ordered a “K” car the Autolite 4100 (4V) with an automatic choke was installed. In 1965 & 1966 they went to a manual choke. Shelby GT350’s were blessed or cursed (opinions waver) with a Holley 4160-C 4V and a manual choke.

All non-“K” cars were equipped with a single point, vacuum advance distributor. “K” cars received the dual-points mechanical advance distributor. All intake manifolds were cast iron except the Shelby versions that were cast aluminum. All engines installed in Mustangs had a cast iron block.

You younger readers may not even know that in the 1960’s you could buy a super premium gas right at the pump! Sunoco was the best as I remember it. Now this stuff was like aviation fuel. Super hot engines like the HiPo 289 thrived on the super premium gas. The “A” code cars used the premium gas. “K” code cars between 1963 and 1965 ran best and the super premium gas after that, premium gas was recommended. Shelbys were to run the super premium and all other cars performed on regular gas. But that was back before the U.S. Government screwed up the gasoline and regular gas was good (and cheap). Good God, is it any reason people hate and distrust the government and its officials.

Engine colors when it first came out were black block and gold valve covers.

In 1963 Ford released the 289 High Performance engine which produced 271 BHP @ 6000 RPM. Stronger connecting rods with 3/8″ bolts, thicker main bearing caps, solid lifter cam, screw-in rocker arm studs, machined valve spring seats, forged steel exhaust valves, a dual point mechanical advance distributor, and better flowing exhaust manifolds rounded out the package. The engines used in the 1965-67 Shelby GT 350 Mustangs, rated at 306 HP, featured a high rise aluminum Cobra intake manifold and Tri-Y headers.

The 289 HP featured a high nodularity cast iron crankshaft that was Brinell hardness tested to ensure quality. To prevent 4th-order harmonic vibrations from destroying the crankshaft at higher RPM, the engine used a different vibration damper and an add-on counterweight. A portion of the 28.2 oz. in. imbalance found in the normal small block damper was moved to the additional counterweight. Moving the mass in towards the front main bearing reduced bending loads on the crankshaft. The special damper also had a larger more massive inertial ring. The add-on counterweight was 0.150″ thick. As a result a special crank sprocket was used, C3OZ-6306-A, itself being 0.150″ thinner than the normal 289 sprocket. The counterweight was both keyed to the crankshaft and indexed to the sprocket with a 1/8″ roll pin

Engine Basics

Engine Specs (206 cid V8)

Clutch information. 289 2v & 4V, 3 & 4 Speeds are the same. Pressure plate is 10 ” w/ 9 springs, Blue cover, purple springs bronze stripe. The disc is 10 ” with 6 springs, green color, orange springs.

Clutch Information. The 289 HiPo 4 speed is a 10.4 inch 9 spring pressure plate. Brown cover, white springs & 2 white stripes. The disc is 10.4, 8 springs, 2 orange stripes & gray springs.

Engine Torque Specifications

All torque specifications provided in this table are those recommended by FORD. If you use special bolts, follow the torque specifications provided by the manufacturer. I recommend that you use the 3 step torque technique where you torque down the bolts in three equal steps. Once you have reached the maximum recommended torque setting, go around one more time. Do not torque in a circular pattern. Always torque cross to cross.

Crankshaft Bearing Journal Specifications

Main Bearing Journal (inches)

Connecting Rod Journals

Piston Ring Specifications

Comp Ring Width

Ring side clearance

Ring gap width

Piston Specifications

Valve Specifications