Flathead V8 Engine Specifications
221 Cubic Inch V8 - 21 Stud

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Early Years: 1932 to 1938


Ford 1933 V8 Engine Shown (pumps in heads)

The first section here will cover the common 221 cubic inch 85hp engines which had 21 studs per head. The displacement remained the same from the 1932 to 1938 versions. Ford started with cast iron heads but changed to aluminum heads for 1933. The aluminum heads were a problem in service and were frequently replaced with cast iron heads. Corrosion made the aluminum erode and become difficult to remove. The engines started out with poured main bearings as earlier Ford engines had used, but the change was made to insert type main bearings late in 1936 production. Production of V8's in 1932 was limited due to initial casting problems with the blocks, causing a high rejection rate. Many 1932 Ford cars were actually equipped with the four cylinder engine for this reason and the concern of the buying public about the reliability of the new V8 engine. The four cylinder engine was dropped in 1933 as production problems and reliability issues with the V8 engines subsided. The 21 stud block was manufactured for partial 1938 model production, with the remainder consisting of the newly introduced 24 stud block.

Early Years 85 hp V8 (Passenger Car) 1932-38

Year Displacement (Cubic Inches) Bore & Stroke (Inches) Maximum Brake HP Compression Ratio Head Studs Notes
1932 221 3.0625 x 3.750 65 5.50:1 21 1,3,5,7
1933 221 3.0625 x 3.750 75 6.30:1 (alum heads) 21 1,3,5,6&7
1934 221 3.0625 x 3.750 85 6.30:1 (alum heads) 21 1,3,5,6
1935 221 3.0625 x 3.750 85 6.30:1 (alum heads) 21 1,3,6
1936 221 3.0625 x 3.750 85 6.30:1 (alum heads) 21 1,4,6
1937 221 3.0625 x 3.750 85 6.12:1 (alum.heads)
7.50:1 (cast iron)
21 2,4,6&7
1938
early
221 3.0625 x 3.750 85 6.12:1 (alum or cast iron heads) 21 2,4,7

Notes
1) Water pumps mounted in the heads.
2) Water pumps mounted in the block.
3) Poured main bearings.
4) Insert type main bearings (Note: late 1936 model engine blocks were usually marked LB*).
5) Did not have camshaft bearings
6) Aluminum heads. Truck engines for these years had cast iron heads. Note that Ford sold replacement heads in cast iron
7) Cast iron heads.

General Information:
The early series flatheads were all 221 cubic (except the smaller 60hp V8 covered in another section). All were cast with the bell housing integral with the cylinder block. All had the "eggshell" (also known as the "Diver's Helmet") shaped distributor mounted to the front of the engine and driven directly off the camshaft. Heads were attached to the cylinder block with hex nuts on studs, which were threaded into the block. There were no Ford factory-built oil filter systems on these engines. Early models used the Detroit Lubricator carburetor. Stromberg "97" carbs were used from 1934 to 1938 at which point a change was made to the Ford designed "94" carburetor. The engine cooling fan was mounted to the generator shaft from 1932  through 1938 (all models).

Ford modified the block for 1935 to incorporate a new crankcase ventilation system. These blocks are evident by the vertical tube located at the right front corner in the valve chamber. The lower right front corner of the block is changed to provide a passage for crankcase ventilation thru the aforementioned tube. The oil pan was also modified to provide a vent at the right front corner of the pan (a triangular shaped "box" with an opening for venting). The differences are seen in this comparison of early blocks (click here). 

* Ford changed the production of main bearings from poured (babbitt) to the removable insert type mid-stream in the 1936 model year. The newer (late '36 production) blocks were supposedly marked with the letters "LB" on the block. Some blocks that had the new style bearings did not receive this marking however. Ford did not use the "LB" marking on the '37 or later blocks.

Early (1932-36) crankshafts had main bearing journals of 1.999". In 1937 the journal size increased to 2.399" Crank pin journals were 1.999" diameter from 1932 up. Cranks were of the "short snout" type. For complete crank bearing specs CLICK HERE. Crankshafts weighed as follows:

1932-34  -  65.6 lbs
1935-36  -  60.0 lbs
1937-38  -  63.8 lbs

Ford records indicate that the 21 stud engine was built up thru December 1937 for new vehicle production. However, the 21 stud engine continued to be manufactured by Ford for other uses (service replacements or industrial engines) until October 4, 1938.

Common features for 1938 V8's were the large hole in the cylinder blocks (seen with heads removed) between the 1st and 2nd cylinders and the 3rd and 4th cylinders on each side. The intake manifold mounting surface was machined flat (no raised area). There were core plugs (often called "freeze plugs") in the oil pan rail. The main bearing caps used studs and nuts to hold them down. There was a ridge (for the pencil resting test) at the front of the block, behind the top of the timing gear cover. Ford started to use the newer 24 stud engine for automobile production in a mid-year change during the 1938 model year.

Horsepower & Torque Curves
Flathead_enginecurves_1932-33_85hp.jpg (122159 bytes)  Flathead_enginecurves_1934-36_85hp.jpg (114548 bytes)  Flathead_enginecurves_1937-38_85hp.jpg (123322 bytes)  Flathead_enginecurves_1939-40_85hp.jpg (132755 bytes)  Flathead_enginecurves_1939-40_95hp.jpg (128516 bytes)
1932-33 (85hp)                           1934-36 (85hp)                           1937-38 (85hp)                           1939-40 (85hp)                           1939-40 (95hp)

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