Model A & B Style

Ford Garage

Cylinder Head Compression Ratios

A variety of cylinder heads and compression ratios have been made for the Model A and B style engines over the years by Ford globally, as well as by aftermarket producers.

Summarized below is a list of cast iron cylinder heads and their combustion chamber shapes and compression ratios for a variety of original applications from 1928 through the mid 1950s, as well as a few more recent examples.


Model A Cylinder Heads:
(Four-stud Water Pump Provision)

Part Number Description Combustion
Chamber
Shape
Combustion
Chamber
Volume (cc)
Compression
Ratio
A-6050-A Ford USA, Global
1928-31 Standard Production head
Model A, 4 bolt water pump
Inch 7/8-18 spark plugs, over intake valves
Also produced by Ford Canada,
Ford England, and Ford Köln Germany
Wedge 242-248 4.2 :1
A-6050-B Ford USA
1931 Production High Compression "Police" head
Model A, 4 bolt water pump
Inch 7/8-18 spark plugs, over intake valves
Marked with a large "B" on top
Can use a Model B head gasket
Heart 178-184 5.2 :1
AF-6050 Ford Dagenham England, 14.9 hp
1928-31 Standard Production 3 inch bore head
Model A, 4 bolt water pump
This head was produced by Ford England
for the 2.2L 14.9 hp Model AF engine
? 144-150 ? :1
A6050A 1940s aftermarket head
Model A, 4 bolt water pump
Inch 7/8-18 spark plugs, over intake valves
Marked "A6050A" and "Made in USA" on top
Copy of Model A Ford combustion chamber
Wedge 242-248 4.2 :1
B6050
Speed Head
1930s aftermarket head
Wrongly marked!
Model A, 4 bolt water pump
Inch 7/8-18 spark plugs, over intake valves
Though marked "B6050 Speed Head" on top,
Actually a copy of a standard Model A
Ford wedge combustion chamber and head,

not an A-6050-B or B-6050 Ford chamber.
Wedge 242-248 4.2 :1
B6050
Speed Head
Early 1930s aftermarket head
Model A, 4 bolt water pump
Inch 7/8-18 spark plugs, over intake valves
Marked "B6050 Speed Head" on top
Copy of a standard Model B Ford B-6050 combustion chamber
Not a copy of Ford part number B-6050 head due to water pump.
Heart 210-216 4.6 :1
A6050B
Speed Head
Late 1930s aftermarket head
Model A, 4 bolt water pump
Inch 7/8-18 spark plugs, over intake valves
Marked "A6050B Speed Head" and "S-S" on top
Copy of Model A Ford A-6050-B "Police" head
Heart 178-184 5.2 :1
F1 MF 1930s aftermarket head
Model A, 4 bolt water pump
Inch 7/8-18 spark plugs, over intake valves
Marked "F1", "MF", and "Made in USA" on top
Copy of Model A Ford combustion chamber
Wedge 242-248 4.2 :1
F2 MF 1930s aftermarket head
Model A, 4 bolt water pump
Inch 7/8-18 spark plugs, over intake valves
Marked "F2", "MF", and "Made in USA" on top
Copy of Model A Ford A-6050-B "Police" head
Heart 178-184 5.2 :1
Snyders Snyders 5.5 aftermarket head
Model A, 4 bolt water pump
Inch 7/8-18 spark plugs, over intake valves
Similar to Model A Ford "Police" head
Uses a Model B head gasket
Heart 5.5 :1
B-F 5.9 Brumfield
1985-2005 aftermarket head
Model A, 4 bolt water pump
Inch 7/8-18 spark plugs, over intake valves
Marked "B-F" on top
Larry Brumfield design combustion chamber
Uses a Fel-Pro 7013 head gasket
Modified
Heart
5.9 :1
Snyders Snyders 6.0 aftermarket head
Model A, 4 bolt water pump
Inch 7/8-18 spark plugs, over intake valves
Bill Stipe design combustion chamber
Uses a Model B head gasket
Modified
Heart
152 6.0 :1
Simmons Simmons Super Power Head
1930-31 aftermarket head
Model A, 4 bolt water pump
Inch 7/8-18 spark plugs, located between valves
Marked "Licensed by Chrysler Motors" on top
Ricardo
Crowfoot
~6 :1
B-F Super Brumfield
1985-2005 aftermarket head
Model A, 4 bolt water pump
Metric 14mm spark plugs, over intake valves
Marked "B-F" on top
Larry Brumfield design combustion chamber
Uses a Fel-Pro 7013 head gasket
Modified
Heart
7.0 :1

Model B Cylinder Heads:
(Three-bolt Water Pump Provision)

Part Number Description Combustion
Chamber
Shape
Combustion
Chamber
Volume (cc)
Compression
Ratio
B-6050 Ford USA, Global
1932-38 Standard Production head
Model B, 3 bolt water pump
Inch 7/8-18 spark plugs, over intake valves
Marked with a large "C" on top
Also produced by Ford Canada, Ford England,
Ford Köln Germany, and Ford GAZ Russia
Heart 210-216 4.6 :1
F3 1930s aftermarket head
Model B, 3 bolt water pump
Inch 7/8-18 spark plugs, over intake valves
Marked with "F3" and "Made in USA" on top
Copy of Model B Ford combustion chamber
Heart 210-216 4.6 :1
M-6050 Ford GAZ (ГАЗ) Russia
1936-43 Standard Production head
Models ГАЗ-AA, ГАЗ-M1, & ГАЗ-67
Model B style, 3 bolt water pump provisions
Metric 18mm spark plugs, over intake valves
Marked with a large "C" on top, and "M-6050"
Heart 210-216 4.6 :1
M-ZM-6050 (?) Ford GAZ (ГАЗ) Russia
1944-53 Standard High Compression head
Model ГАЗ-67B
Model B style, 3 bolt water pump provisions
Metric ?mm spark plugs, over intake valves
? ? ? :1
BG-6050-B Ford Köln Germany
1930s Wood Gas Generator head (Imbert)
Model B, 3 bolt water pump
Inch 7/8-18 (or metric 18mm?) spark plugs
Marked "BG-6050-B" on top
For use with poured babbitt bearings
(mit ausgegossenen Lagern)
? 123-125 7.0 :1
G98T-6050 Ford Köln Germany
1939-42 Standard Production head
Model B style, 3 bolt water pump provisions
Metric 14mm spark plugs
Marked "G98T-6050" on top
same as B-6050 except for spark plug size
Heart 210-216 4.6 :1
G28TG-6050 Ford Köln Germany
1942 Wood Gas Generator head (Imbert)
Model B style, 3 bolt water pump provisions
Metric 14mm spark plugs
Marked "G28TG-6050" on top
For use with shell bearings (mit Lagerschalen)
? 94-96 8.5 :1
G38T-6050 Ford Köln Germany
1943-58 Standard Production head
Model B style, 3 bolt water pump provisions
Metric 14mm spark plugs
Marked "G38T-6050" on top
What is difference to "G98T-6050" ?
Heart 210-216 4.6 :1
BF-6050 Ford Dagenham England, 14.9 hp
1932-36 Standard Production 3 inch bore head
Model B, 3 bolt water pump
Inch 7/8-18 spark plugs
This head was produced by Ford England
for the 2.2L 14.9 R.A.C. hp Model BF engine
Only fits the Model BF engine block, no others
Mouse
Ears
100 psi 5.2 :1

Five different compression ratio cylinder heads were made for the Model A and B standard bore engine by Ford Motor Company themselves.

The following graph is derived by plotting the Ford-published data of the combustion chamber volume on the part drawing against the Ford-published data of the compression ratio of each head.

The compression ratio of an unknown flat head can be closely estimated by measuring the combustion chamber volume and reading the CR off the graph above. The estimation would approximate the compression ratio that Ford would have claimed for that head using their measurement methods and calculations on a standard bore engine.


Thanks to Marco Tahtaras for allowing the use of his photo and method of measuring combustion chamber cc's here on Ford Garage!


More related information on Ford Garage:

  1. Model A & B Cylinder Head Comparison
  2. Model A Simmons High Compression Cylinder Head
  3. Model B Russian GAZ Cylinder Head  
  4. Model A Brumfield Cylinder Head and Gaskets
  5. Model A & B Model C Myth and Terminology
  6. Model A & B Cylinder Head Gasket Guide comprehensive listing
  7. Model A & B Cylinder Head Nut Tightening Sequence
  8. Model A & B Snap-On Cylinder Head Nut Wrench proper torque application tool
  9. Model A & B Cylinder Head Flatness Requirements by Larry Brumfield
  10. Model A & B Cylinder Head Gasket Installation Instructions by Larry Brumfield
  11. Model A & B Broken Cylinder Head Stud and Bolt Removal
  12. Model A & B Cylinder Head Stud Removal Tools

April 2013