First V8, the Commander:

The first Studebaker V8 engine was introduced in the Commander for the 1951 Model year.  Only Cadillac and Oldsmobile were manufacturing an OHV V8 at the time of release.   It was completely designed in house by Studebaker engineers under the direction of Stanwood W. Sparrow.  It replaced the 245.6 cubic inch L-head six which had been used in the most recent Commanders.  The displacement was 232.6 cubic inches with and over-square 3 3/8 inch by 3 ¼ inch bore and stroke.   It made 120 HP at 4,000 RPM and 190 foot pounds of torque at 2,000 RPM.  It featured solid lifters and a compression ratio of 7.0 to 1.  A very strong crankshaft was held in five main bearings.

Revisions:

1954, increase in the compression ratio to 7.5 to 1, results in the engine making 127 HP.   The truck line began using the 232 V8 engine.

1955, the President “Wildcat” engine is introduced in the newly release President.  It bore was 3 9/16 inch with a stroke of 3 ¼ (259.2 cubic inches).   Four-barrel carburetor was standard and this engine made 175 HP.   The Commander “Pace-setter” this super over-square engine with a stroke of only 2 13/16 of an inch and the same bore at the Wildcat engine displaces 224.3 cubic inches and produces 140 HP.   The fuel pump is moved from the top of the engine to the side and both engines now have larger valves.  Optional compression ratio of 8.0 to 1 was available in both engines, but resulting HP are not available in my research.  The truck line began using the 224 V8 engine.

January 1955, the “Wildcat” engine is renamed “Passmaster” and given 10 more HP (185).  Except for duel exhaust, no other changes were noted.  The Commander's engine is now called the “Bearcat”, the stroke was increased to 3 ¼ inch (259.2 cubic inches), making 162 HP.   With the optional four-barrel carburetor, it made 182 HP.   There were no significant differences between the optional Commander engine and the President engine so the 3 HP difference can only be attributed to advertising.  Most Studebaker V8 experts would tell us that the “Pace-setter” Commander engine was no pace setter at all.  The truck line began using the 224 engine (E7, E12,E13). The 259 engine was used on the larger trucks (E28, E38).

1956, the stroke is increased to 3 5/8 (289 cubic inches), 195 HP, for the President sedans, and the Sky Hawk. 210 HP with four-barrel carburetor.   The 259 engine used in the Commander sedans and the Power Hawk, are now rated at 170 HP, 185 HP with the optional four-barrel carburetor.  Both engines had a compression ratio of 7.5 to 1 and are called “Sweepstakes”.

1957, the President's 289 and the Commander's 259 engine, compression ratio is raised to 8.0 to 1 increasing the HP to 210 and 180 respectively.   The four-barrel carburetor option would increase the HP to 225 and 195.  The Packard Clipper Sedans and the Studebaker Golden Hawk used the 289 engine with the Paxton Supercharger, making 275 HP.   The domestic Silver Hawk used the 289 – 210 HP engine (225 with four-barrel).   The Canadian Silver Hawks used the 259 – 180 HP (195 with four-barrel).  The truck line replaced the 224 V8 with the 259 V8 and the new 3E40 used the 289 engine.

1958, the Packard Hawk is released and uses the Supercharged 289 engine, making 275 HP.   All other sedan and Hawk engine specifications remained the same as 1957.

1959, only the Silver Hawk remains, using the 259 engine.  The sedans are replaced with Larks.   The Packard Hawk and Golden Hawk are dropped.   The Lark VIII used the 259 engine, only the trucks used the 289 engine this year.   While compression ratio's may have changed somewhat, the HP ratings stayed the same as 1957.  The 289 engine is available on all V8 truck models.

1960 – 1961, all Hawks use the 289 engine – 210 HP (225 with four-barrel).  Lark VIII continued to use the 259 engine.  In 1961 the Cruiser could be had with the 289 engine as an option.  Full flow oil filters are added to both engines.

1962, the Lark VIII uses the 259 engine as it's standard, while the GT Hawk uses the 289.  However all models can be ordered with the 289 engine as an option.  HP of both remain the same as 1957.

1963,Avanti engines: 

R1- 289 with new cam, 10.25 to 1 compression ratio, 240 HP.

R2 – Supercharged 289 with compression ratio of 9.0 to 1, 289 HP.

R3 – 305 cubic inch engine (bored out 289), supercharged with new cam and larger valves, 9.75 to 1 compression, 335 HP.

R4 – Same as R3 except not supercharged, instead fueled by a pair of four-barrel carburetors and used a compression ratio of 11 to 1, 280 HP. 

All the Avanti engine options were derivatives of the 1956 289 engine.   The GT Hawk used the 289 engine as it's standard , while the Larks, used the 259 engine as it's standard, except for the Crusier which used the 289 engine.   However all Hawks and Larks could option the 289 or any of the Avanti R engines.   The engine names were changed to Thunderbolt for the standard 289, Power Thrust for the standard 259, and all R engines were called JetThrust.

1964, the Gt Hawk used the 289 engine, and the Larks (however not called Larks any more), used the 259 engine, except the Cruiser which used the 289 engine.  By December of 1963, the end of the Studebaker V8 came to a conclusion as the South Bend Plant was closed forever.