Cadillac Models & History 1908

Cadillac fielded five models: Model G, Model H, Model M, Model S, and Model T.


  • The 1908 Model G was virtually the same as the 1907 Model G except a limousine was added to the line.
  • One or two passenger rumble seats were available, but of a different pattern than the single rumble seat model of 1907.
  • There were no changes in the Model G engine for 1908, but the advertised horsepower rating was increased from 20 to 25.
  • This was due to the newly instituted ALAM horsepower formula, which gave the Model G a horsepower rating of 25.6.
  • Cadillac had always been conservative in horsepower ratings.
  • The ALAM rating was also conservative, and gave the same rating to every engine with the same bore and number of cylinders.
  • There was no allowance for design, accuracy or precision of manufacture, superior practice in fit and tolerance, etc.
  • Although having had a voice in establishing the ALAM formula, Cadillac soon took exception to being rated the same as the least sophisticated manufacturer.
  • Although engines were tested for actual developed horsepower, it was to be many years before horsepower curves were publicized.



Description Four cylinder, L-head Individual cast iron cyl., copper water jacket
Bore & Stroke 4 x 4.5 in. (101.6mm x 114.3mm)
Displacement 226.2 cu. in. (3.707 liters)
ALAM H.P. 25.6 hp
Advertised H.P. 25 hp
Main bearings Five
Valve lifters mechanical
Carburetor throttled float feed, jet type made by Cadillac


Wheelbase 100 in.
Front/Rear tread 56 in.
Tire 32 x 3.5 (34 x 4 limo)


Description Cylinders cast singly, copper water jackets, detachable combustion valve chamber
Main bearings replaceable without removing crankshaft
Valves interchangeable inlet and exhaust valves operated by push rod & roller cam follower on single gear driven camshaft
Accessories belt driven fan, water pump, and oiler; splash lubrication
Suspension three point engine suspension
Cranking clockwise cranking
Carburetor float feed carburetor controlled by foot throttle or automatic ring-type governor; jet type carburetor made by Cadillac
Transmission type selective sliding gear transmission, independently attached to frame

The MODEL H for 1908 was the same as the 1907 Model H except the coupe body was dropped from the line. Also the touring body was now similar to the Model G with continuous molding across the center of the doors. The model H no longer supplied an engine speed governor or the interlock between brakes and clutch. Tire size increased to 34 x 4.

The MODEL M was built only as a delivery vehicle. It was the same as the 1907 delivery except that prices now included two oil side lamps, an oil tail lamp, and a bulb horn. Headlamps were not included as standard equipment on Cadillacs until 1910. Also it did not have the longer wheelbase or running boards found on the Model S or Model T.

The MODEL S has the same chassis as the 1907 model except the wheelbase on all body styles increased to 82 in. and full running boards replaced the step plates. Single and double rumble seat options were available on the straight line or Victoria styles runabouts. If rumble seat passengers were to be carried regularly, it was recommended that tire size be increased from 30 x 3 to 30 x 3-1/2.

The MODEL T has the same chassis as the Model S except the coupe did not have running boards. The bodies were the same as the 1907 Model M except the folding tonneau was dropped. The Victoria style top was now available for the tonneau of the Victoria Touring.


Model G & H serial numbers on plate on rear of body or on dash (with engine no.);
engine numbers were stamped on top surface of crankcase
– in front of and to the left of number one (front) cylinder.
Model G engine no. 30426-30500 (1907- 1908), 30501-31032 (1908)
Model H engine no. 10201-10709 (1906-1908).
Model M, S & T serial numbers on plate on rear of body (with engine number.
Engine numbers were stamped two places on crankcase:
1. Top, right edge of cylinder flange, near water outlet.
2. Top surface of left, front mounting leg.
Also on plate on rear of body (with serial number).
(Blank spaces on patent plate are for additional patent dates, not engine or serial number.)
Model M engine no. 24075-24350 with K, S. T (1907).
Model S engine no. 24075-24350 with K,- M, T (1907), 24351-25832 with T.
Model T engine no. 24075-24350 with K. M. S (1907), 24351-25832 with S.


Body Type & Seating
Model G
2-dr. Tr.-5P $2000
2-dr. Limo.-5P $3000
Runabout. – 3P $2000
Runabout – 4P $2025
Model H
2-dr. Tr.-5P $2500
2-dr. Limo. – 6P $3600
Runabout – 2P $2400
Model M
Delivery – 2P $950
Model S
Straight Line Runabout – 2P $850
Vic. Runabout. – 2P $850
Vic. Runabout w/single rumble $875
St. Line Runabout w/double rumble $885
Model T
2-dr – St. Line Tr. – 4P $1000
2-dr. Vic. Tr. – 4P $1000
2-dr. Coupe – 2P $1350


Model H Model G Model M, S, T
Engine type Vertical, in-line, L-head. Four. Individual cast iron cyl., copper water jacket. Horizontal, with cylinder to rear. One cylinder. Cast iron cylinder, with copper water jacket
Bore & stroke 4.375″ x 5.00″ (111.1mm x 127mm) 4.00 x 4.50″ (101.6mm x 114.3mm) 5.00 x 5.00″ (127mm x 127mm)
Displacement 300.7 cid (4.927 liters) 226.2 cid (3.707 liters) 98.2 cid (1.609 liters)
Brake HP “Higher than advertised or calculated”
ALAM HP 30.625 25.6 10
Advertised HP 30 25 10
Main bearings 5 5 2
Valve lifters mechanical
Carburetor throttled, float feed, jet type made by Cadillac Updraft mixer manufactured by Cadillac


Model M Delivery Model S Model T Touring Model T Coupe Model G Model H
Wheelbase 76 in. 82 in. 82 in. 82 in. 100 in. 102 in.
Front/Rear Tread 56 in. 56 in. (61 in. opt.) 56 in. (61 in. opt.) 56 in. (61 in. opt.) 56 in. 56.5 in.
Overall length 10′ 1″ 10′ 2″
Height 5′ 4″ 5′ 4″
Tires 30 x 3-1/2 30 x 3 30 x 3-1/2 30 x 3-1/2 32 x 3-1/2 (34 x 4 limo) 34 x 4


Feature Model G Model H Models M, S, and T
Transmission Selective sliding gear transmission Planetary transmission Planetary transmission
Speeds 3 Forward, 1 Reverse 3 Forward, 1 Reverse 2 Forward (3:1 and 1:1), Reverse (3:1)
Drive control Right-hand drive with controls to the right Right-hand drive with controls to the right Low (foot pedal), reverse & high (lever to the right)
Clutch Leather faced cone clutch Twin disc in flywheel, disc and three bands on transmission disc clutch
Drive Shaft drive Shaft drive Chain drive
Axle Live axle, bevel drive Live axle, bevel drive
Differential Spur gear Bevel differential Spur gear
Overall ratio 3.1:1 to 5:1
Brakes Mechanical brakes on two wheels; service and emergency brakes on rear drums Mechanical brakes on two wheels; service and emergency brakes on rear drums Mechanical brakes on two wheels; contrac- ting on inboard drums
Wheels Wood artillery wheels, 10 spokes front, 12 spokes rear Wood artillery wheels, 12 spokes front, 12 spokes rear Wood wheels, 12 spokes
Touring & Roadster Wheel size 25 in.
26 in. Model M and T=23 in.
Model S=24 in.


  • On the models M, S & T, different combinations of 9 or 10 tooth driving sprocket with 31, 34, 38, 41, or 45 tooth driven sprocket gave ten possible ratios from 3.1:1 to 5:1.
  • Driven Sprocket
    31 34 38 41 45
    9 tooth drive sprocket 3.44 3.78 4.22 4.56 5.00
    10 tooth drive sprocket 3.10 3.40 3.80 4.10 4.50
  • Lower ratios for runabout to be run on smooth, level roads to higher ratios for loaded Delivery to be run on rough, hilly roads.
  • Instructions for changing sprockets were available for owners, but the change involved disassembly of the transmission and rear axle — definitely not a “quick-change” set-up.


Model G: Headlights. Rubber, leather, and mohair tops in three-bow, cape cart, and victoria styles $90.00 to 200.00
Model H: Headlights. Lined Cape Cart top for Touring $150.00
Model S: Headlights. 30 x 3-1/2 tires on Runabouts with rumble $50.00
Model S: Rubber top with side curtains & storm apron $60.00
Model S: Leather top with side curtains & storm apron $80.00
Model S: Victoria style top (factory installed only) $175.00
Model S: Storm front w/windows to replace storm apron $15.00
Model T: Headlights. Cape Cart top $115.00
Victoria style top (factory installed only) $175.00


The model G was introduced in November, 1907. Calendar year sales and production was 1030 (1907-1908). Model year sales and production: same. The President of Cadillac was C. A. Black.

Note: The bulky, complicated, planetary transmission luxury fours were too great a first leap from the single cylinder, which had become passe. The compromised Model G design formed a solid basis for the “Thirty,” which was to be the single line for Cadillac through 1914. Had the Brush design concepts been perpetuated, the company might well have failed. Its move into a firm position in the luxury car field was to wait another seven years.

The model H was introduced in June, 1907. Calendar year sales and production: 509 (1906- 1908). Model year sales and production: same.

Note: This was the last year for the planetary transmission fours and the counterclockwise cranking for Cadillac. The only remaining Brush features were the copper water jacket and the splash lube system; both of these were in use by Cadillac through 1914.

The model M was introduced in 1906. Model year production was included with the 1907 figures.

The models S & T were introduced on Nov. 1907. Calendar year sales and production: 1482 with S & T. Model year sales and production: same.

Note: Several hundred of the approximately 16,000 single cylinder Cadillacs produced still exist in the hands of collectors all over the world. A prominent Australian collector visiting Hershey remarked, “Anyone wanting to restore, drive, and enjoy a one cylinder car had best find a Cadillac” — no argument, mate.