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Oil Pump Specifications

Type: Pump, splash, gravity feed

Crankshaft Bearings: Gravity feed

Connecting Rods: Splash

Camshaft Bearings: Gravity feed

Oil Pump Type: Gear

Oil Pump Capacity: 9 pints, minimum at 1300 rpm

Oil Pump Pressure: 80-100 pounds

Oil Pump Shaft: 1/2" diameter (in 5/8" bore), except 1928 with 9/16" bore & undercut shaft (Model B used 5/8" bore with undercut shaft)

Oil Pump Gear Teeth to Housing Clearance: .001" to .002"

Housing Cover to Face of Gears Clearance: .001" to .002"

Drive Gear to Camshaft Gear Clearance: .003" to .005"


Transmission Specifications

Gear & Shaft Material: Chromium alloy steel

Gear Ratios:
High-1:1 (100%)
2nd-6.89:1 (53.8%)
Low-8.75:1 (32.04%)

Main shaft front (ball) 1208;
Main shaft rear (ball) 1306

Transmission Case Length: 6.560" to 6.565"

Case Front Bearing Hole: 3.1497" to 3.1507" diameter

Case Rear Bearing Hole: 2.835" to 2.836" diameter


Clutch Specifications

Material: Molded asbestos composition

Pressure Plate Weight: 15 pounds

Clutch Disc Weight: 2-1/2 pounds

Pivot Pedal Pressure: 30 pounds

Clutch Facings: 9" diameter, 9/64" thick

Inside Diameter: 5-3/4"

Total Acting Surface Area: 75 square inches

Clutch Pedal Clearance: 3/4" for multiple disc, 1" for single

Clutch Release Bearing Hub: 2.065" diameter

Clutch Throw Out Bearing: B7580 or B7580T

Clutch Pressure: 1100 pounds


Radiator Specifications

1928 Manufacturer Ford

1929 Manufacturer Flintcock, Long, McCord

1930-31 Manufacturer Ford


Standard Radiators 1928-29

Tubes Flat 1/2" seamless

Number of Tubes 101 in 3 rows, staggered at 9/16" centers

Number of Fins 5 fins/inch-98 fins

Core Size 19-3/4" x 19-1/8" x 2-3/16" centers

1928-29 Heavy Duty 8 fins/inch-158 fins


Standard Radiators 1930-31

Tubes Flat 1/2" seamless

Number of Tubes 95 in 3 rows, staggered at 9/16" centers

Number of Fins 5 fins/inch-100 fins

Core Size 20-1/8" x 18" x 2-3/16" centers

1930-31 Heavy Duty 8 fins/inch-167 fins


Zenith Carburetor Specifications

Throat Size: 1"

Float Level: 5/8" below upper body machined surface. Model B, 33/64" below upper body machined surface.

Main Jet: .037" ID (#63 drill bit)

Cap Jet: .037" ID

Compensator Jet: .035" ID (#65 drill bit)

Idling Jet: .021" ID (#75 drill bit)


How to Tell if You Have a Zenith or a Tillotson Carburetor?

It’s easy. The original Zenith carburetors had round-shaped cast iron bodies, while Tillotson carburetors were made of an aluminum alloy, with more of a “boxy” shape. Usually, Zenith carburetors are found painted black, while Tillotsons are normally unpainted aluminum color.


Water Pump Specifications

Water Pump Shaft: 5/8" diameter
Water Pump Shaft End Play: .006" to .010"
Radiator Hose:
Upper: 2" diameter, 6-1/4" long (28-29) 8" long (30-31).
Lower: (2 pieces) 1-3/4" diameter,
2-3/4" long.


Fan Blade & Belt Specifications

Fan Belt Width: 5/8"

Fan Belt Length: 42-7/8"

Fan Cooling Surface: 374 square inches

Fan Speed: 1-1/2 times engine rpm. Fan delivers about 855 cfm at 1,000 rpm, about 24 mph

4 Blade Fan: At 1,000 rpm, 62% increase in air flow,
82% increase in HP absorbed; at 2,000
rpm, 55% increase in air flow, 47%
increase in HP absorbed.


Gas Tank Specifications

Steel Thickness: .049" to .051" (terne plated)
Capacity: 28-29: 10 gallons 30-31: 11 gallons


Generator Specifications

Type: Two pole

Voltage Regulation: Fixed control

Brushes: 3 (1 adjustable)

Armature Bearings:
29-Mid ’30: Ball front & rear
After Mid 30: Ball front, bushing rear

Armature Speed: 1-1/2 of engine speed

Armature Length: 28-April ’30: 7-9/16" - uses 1-5/32" wide pulley
after April 30: 7-21/32" - uses 7/8" wide pulley

Max. Normal Charging Rate: 12 amps @ armature 1600 rpm (25mph)

Cutout Closes: Approximately 9 mph

Cutout Opens: Approximately 8 mph

Contact Gap: .015" to .020"

Core Gap: .010" (contacts closed)

Brush Spring Tension: 25 to 40 ounces each

Field Coils: 100 turns of #17 copper wire

Armature: 14 coils with 6 turns of #17 copper wire

Commutator: 28 copper segments

Field Current Draw: 6.3 amps at 7 volts, generator
(motoring draws 5.75 amps at 7 volts)

Maximum Current: 18 to 22 amps at 6 volts

Motoring Freely: 5 amps at 6 volts

Field Test: 5.2 amps at 6 volts

The very earliest Model A Fords were equipped with “Powerhouse” generators (shown below), which had a pancake shape & a body covered with sheet metal. Soon Ford replaced them with the more familiar generator that is shown below. These generators, when working properly, are simple, durable & reliable.

Photo Captions:
1. Cut-Out
2. Cover band
3. Pulley
4. Rear End Plate


Battery Specifications

Terminal Grounded Positive

Voltage 6 volt

Capacity 80 amp hours, starting capacity 98 amps

Number of Cells 3

Number of Plates 13 per cell

Charging Rate 10 to 12 amps


Starter Motor Specifications

Type of Drive: Bendix (except early 1928)

Terminal Grounded: Positive

Rotation: Counterclockwise (viewed from commutator or bushing end)

Armature: 21 segments

Brush spring: 35 to 40 ounces

Running Free
Test Data


Distributor Assembly Specifications

Rotor Revolution Direction: Counterclockwise

Point Gap: .018" to .022"

Point Spring Tension: 16 to 18 oz.

Condenser Capacity: .20 to .25 mfd

Yellow Wire Ignition Circuit: 12 gauge

All Other Wiring: (except high tension circuit) 16 gauge

Camshaft to Bearing Clearance: .001" to .002"

Spark Control Manual Advance: 20° (28° camshaft travel)

Rotor End Cap to Distributor Terminal: .020"

Ignition Circuit: .62 amps at 6.2 volts (engine at 1500 rpm)
4 amps at 6.2 volts (engine stopped)

Set point gap at .018"-.022" (.022" for new points). The rubbing block on the points will wear down .003"-.005" after approximately 400-1,000 miles. After this point, wear might only be .001" over the next 10,000 miles. Therefore, be sure to reset the point opening to .022" by the end of the first 1,000 miles.


Spark Plug Specifications

Spark Plugs: Champion 3X, 7/8" x 18 thread

Spark Plug Gap:
.035" (A6050A cylinder head),
.030" (B6050 cylinder head),
.025" (A6050B cylinder head)


Interior Lights Specifications

Instrument Panel: 3 candle power, single contact, B13466

Dome: 3 candle power, single contact, B13466

Commercial Dome: 21 candle power, single contact, B13465



Wiring Books


Year: 1928-1931

Part #: A14000/1



Year: 1928-1931

Part #: A14000/2




Cylinder Block Specifications

Length: 19-5/16"

Width: 7-13/16"

Height: 11-1/2"

Bore: 3.875" to 3.876"

Bottom of Block to Camshaft Centerline: 2.876" to 2.878"

Top of Block to Camshaft Bore Centerline: 8.624" to 8.627"

Valve Lifter & Guide Bore: .594" to .5945" diameter

Distributor Drive Gear Bore: .9365" to .9375" diameter

Cylinder Outside Diameter: 4-3/8" outside diameter

Flatness of Top of Block: .003" to .005"

Cylinder Bore Perpendicular
to the Top of the Block:
.001" to .002"


Windshield Wiper Information

From the start of production, the Model A was equipped with windshield wipers. Early wipers were either manual (commercial & open car) or electric (closed car). All ’28 electric wipers were made by the Owen-Dyneto Company, who used zinc die-castings (also known as pot metal) for the base, cover & levers. This was a very brittle metal that broke & warped over the years, leaving very few intact wipers.

Beginning in February ’29, Ford began using electric wipers from Heinz Electric Company & in March ’29 from E.A. Laboratories, Inc. These new wipers were made from pressed steel & were much more durable.


General Sheet Metal Information

When faced with rusted or missing Model A sheet metal, yesterday’s restorer had to rely on used metal panels & body parts from a dry climate, or hand-made panels hammered out by highly talented metalsmiths.

But today, MAC's Antique Auto Parts is proud to offer a tremendous selection of precision-crafted sheet metal panels & components for many different Model A body styles. Like the original panels, MAC's sheet metal parts are die stamped from heavy gauge steel, with correct flanges, contours & seams as original. You’ll like working with new solid steel instead of thin & rust-weakened panels full of body filler.

As with any new body part, these panels might require some fitting & minor metal work & must be welded by a competent body person. Return that new-steel “solid” feeling to your Model A with brand new steel sheet metal parts & panels from MAC's!


Hood Specifications



The content MAC's presents on its "Vehicle Identification & Specification" pages & in its catalogs is for information use only and is intended to be used as a guide. While MAC's makes every effort to ensure accurate content, occasionally errors may occur. MAC's does not take responsibility & will not be held liable for any automotive parts purchases, repairs or restoration decisions made as a result of information presented here or anywhere in its catalogs.


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