The reasons for the small blocks popularity over its five decade life span can be attributed to its compact light weight and a strong support team with a wide variety of parts readily available. All the Chevy V8 engines from the early “W”, to the big blocks including today’s LS7 and LS9 have evolved from the original 265 small block. This engine is categorized in families by bore size; with the first two in engines in the original family, the 265 and the 283 going into automotive history.
The 3.875 inch bore family from 1955 to 1973-three members:
The start of the long procession of small block V8’s is the 265 which has a two year production run before evolving into the 283. The 265 was initially produced to give the Corvette a more powerful engine than the inline stove bolt six used in the 1955 models. From the design studio to the production floor took only 15 weeks for Ed Cole and his team for the original two barrel carburetor 165 hp (123 kW) version. The engine is a cast iron block, cast push rods, with hydraulic lifters; the power plant is oversquare with a 3.75 inch (95 mm) bore and a 3 inch (76 mm) stroke-for many decades the 4.4 inch (111.8 mm) bore spacing would remain a standard. The Bel Air for ’55 came with a two barrel developing 162 hp (11 kW) but with the option of a Rochester four barrel added giving the engine 195 hp (145 kW). A further option is the “power pack” which adds a dual exhaust and with the four barrel the Bel Air delivers 180 hp (134 kW). The 1955 Corvette had three power option 265 engines; the single four barrel delivers 210 hp (157 kW), the twin four barrels offer 225 hp (168 kW), or added to those for the ultimate Corvette in ’55 is with the high lift camshaft which gives the ‘Vette 240 hp (179 kW).The 265 is not an engine for a casual owner or regular driver in spite of its original sand cast green color-it is a collector’s item only because it lacks adequate oil filtration with its add-on filter.
The 283 cu in (4.64 L) engine is a 265 bored to 3.875 inches (98.4 mm) with a 3.00 inch stroke which becomes available for the 1957 model year. These first versions used the original 265 blocks and they are overbored which make for thin walled cylinders. The later 283 engines were cast with thicker walled blocks to accept the larger bore. There are five power versions of the 283 available offering from the carbureted entry level two barrel putting out 185 hp (138 kW) or with twin carburetors gives a few more horses. With the Ramjet mechanical fuel injection the 283 achieves 283 hp (211 kW)-one hp for each cu in displacement in the 1957 model year. This however, is not the first engine to reach the goal Chrysler did the same in the 1956 model year. The horse power ratings increased each year with the 283 topping out in 1961, still using the injection at 315 hp (231.68 kW). The Chevy 283 was also available for the Checker Cab line up and in Canada the Studebakers for ’65 and ’66 could be ordered with this engine
The last of the 3.875 inch bore family is the 307 (5.025 L)-the higher displacement is attained by increasing the stroke to 3.25 inches (82.6 mm) and was the standard V8 offered from 1968 through 1973. The 327 engine is the source of the crankshaft which offers the longer stroke. The engine is also used by GMC in South Africa and the Australian Holden subsidiaries.