1966 Mustang Coupe  Information


General Information

The 1966 Mustang coupe is a 289 cubic inch eight cylinder engine with a 2 barrel carburetor. The exterior color is called "Springtime Yellow". The car was repainted one time and it was not a very good paint job. I will have repainted the car prior to selling it.

The 1966 Mustang body was almost identical to the 1965 Mustang.   Because of the extremely high demand for the cars, Ford could barely keep up with demand by running full speed in three assembly plants.  Therefore, few changes were made between the early '65s and the late 1966 Mustangs. Most body panels are identical. The grille on the 1966 consisted of a series of horizontal chrome bars and in the center was a running horse in a corral. On the side of the car, back where the faux air scoops were, they changed the "C" scoops to a three finger side marking. The gas cap was changed in 1966. Between 9 & 10 percent of the Mustangs were equipped with a vinyl roof. The padded sun visors became standard in 1966.

The optional V-8s in 1966 were the 289ci 2bbl engine rated at 164 hp engines and then the 289ci 4bbl 210 hp engine. and the 289 HiPo engine rated at 271 horsepower.

The 289 2bbl engine in this 1966 Mustang produced 165 horsepower with the use a an Autolite 2100 2bbl carburetor. Valve sizes in all the 289 engines were identical.

The default transmission in 1966 was the 3 speed manual.  However for a few measly dollars more one could buy either an automatic transmission or a 4-speed manual tranny. Most cars in 1966 were ordered or equipped with the Cruise-O-Matic transmission. The second most ordered transmission was the standard 3-speed which is what this car has. 4-speed transmissions were the rarest transmissions ordered in 1966.

Interiors for 1966 consisted of the standard or plain Jane interiors, which by standards of the day were still fancy. The '66 Mustang seats have a woven pattern and the inside door panels have a horizontal line pattern opposed to the vertical pattern found on the '65 models. Door handles and window cranks remain unchanged except the migrated to a center screw to hold teh handles on and not a rear mounted clip.

Starting in 1965, V8 cars standard rims were the 4.5x14 and use 6.95x14 tires, 15x5 wheels were an option and used 5.90x15 tires. The 15 inch option was dropped and late hi performance cars used 14 inch rims and dual red line sidewall tires.


The 2100 2V carburetor is specific to each engine and transmission combination. 2100 carburetors were made for both small and big block engines. Big block carburetors cannot be used on small block engines because the butterfly valves hit the manifold openings and stop the throttle from opening all the way. Manufacturing tags were not used until 1965 but, the throttle bore size can be found cast into the body of the carb on the drivers side towards the front.

The 280 and 289 engine 2100 carbs had a 1.145 inch venturi opening which translates to about 300 cfm. Cars bound for California received smaller jets as did cars bound for higher elevations.

The following information is for mechanics only and will have little meaning for the general population. The carburetor is a C6OF-A,

Throttle Bore 1.437 Venturi Diameter 1.145
Main Metering Jet 51F - 49_F Power Valve RED
Choke Spring TW Choke Spring Setting 2 rich
Choke Plate Setting 0.110 - 0.130 Accelerator Pump Setting Inboard
Throttle Lever Hole 3 Dry Float Setting 0.491
Fuel Level Wet .875 Fast Idle 1600 RPM
Curb Idle 450 - 500 Antistall Dashpot 0.060 - 0.090



The car is equipped with a single exhaust system. A single muffler is mounted parallel and to the rear of the axle. The exhaust system looks to be in great condition.


The 1966 Mustang has a vacuum line from the intake to the distributor and that is the only vacuum line on the vehicle. Simple but effective. The vacuum line is new.

Wheels and Tires

The tires are in good shape. The rims are standard 14" rims and the hub caps are the highly sought after wire spoke hubcaps with the spinners and Mustang inserts. The hubcaps are in very good condition.

289 Engine Tune-up Specifications

Year Engine Spark Plugs Distributor TimingÂș Intake Valve opens Fuel pump press Idle speed
Cyl cid HP Type Gap Dwell Gap Man A/T Man A/t
1966 8-289 200 BF-42 .034 29 .017 6B 6B 16 4.5 600 (635) 500



Model Engine Oil Transmission (pts to add after draining) Axle Gas tank Cooling system
3 Spd 4 Spd Auto Qt. w/ heater with AC
8 - 289 5 3.5 3.5 17 4.5 16 15 -




CENTRIFUGAL ADVANCE - perform test at 250 RPM and 0 inches of mercury
Distributor RPM
Advance Degrees
Vacuum inches of mercury
1.5 - 2.5
5.25 - 6.25
7.25 - 8.25
8.75 - 10
110.5 - 12
Maximum advance limit is 14.0 degrees
VACUUM ADVANCE - perform test at 0 degrees and 1000 RPM with 0 inches of mercury
Distributor RPM
Advance Degrees
Vacuum inches of mercury
1.5 - 4.75
5 - 8
8.25 - 11
Maximum advance limit is 12.5 degrees


289 and 390 cubic inch V8 engines all had a breaker arm spring tension of 17-21 ounces. contact spacing was 0.017 and the dwell at idle speed was 26-31 degrees. 289 end shaft play with the distributor removed is 0.024-0.035 inches while the 390's end shaft play is 0.022-0.032 inches. The distance from the bottom of the mounting flange to the bottom of the gear for the 289 is 4.0131-4.038 inches and for the 390 is 3.071-3.077 inches. Timing for 289 ci engines with a manual transmission or automatic is 6 degrees before top dead center (BTDC). Timing for a 390 is 10 degrees BTDC.