Engines Pontiac

pontiac engineer clayton leach designed stamped steel valvetrain rocker arm, simplified , reliable alternative bearing-equipped rocker. design subsequently picked every ohv engine manufacturer @ 1 point or another.

pontiac began work on v8 configuration in 1946. intended l-head engine, , 8 experimental units built , extensively tested end of 1940s. testing comparisons ohv oldsmobile v8 revealed l-head not compete performance-wise. so, in addition building new pontiac engineering building in 1949–1951, decision re-direct v8 ohv design delayed introduction until 1953 model year, buick division introducing new engine (nailhead v-8) in 1953 , asked corporation hold or delay pontiac s v-8 introduction until 1955 model year did.

in mid-1956, pontiac introduced higher-powered version of v8. among other things, version of engine equipped high-performance racing camshaft , dual 4-barrel carburetors. first in series of nascar-ready pre- super-duty v8 engines , introduced long line of multi-carburetor equipped engines saw pontiac become major player during muscle car , pony car era of 1960s. interestingly, enlarged 1956 pontiac v8 found way light-duty gmc pickup trucks.

pontiac s second generation v8 engines shared numerous similarities, allowing many parts interchange advent in 1959 demise in 1979. sizes ranged 287 cubic inch 455 cubic inch. similarity (except 301 & 265) makes rebuilding these engines relatively easier. feature made possible pontiac invent modern muscle car, relatively simple process of placing second largest-displacement engine, 389 cid, mid-size car, le mans, creating pontiac lemans gto.

from inception in 1950s until 1970s, pontiac engines known performance. largest engine massive 455 cubic inch v8 available in of mid-size, full-size , sports car models. @ height of horsepower era, pontiac engines reached powerful 390 rated horsepower (sae gross), though other engines achieved considerably higher outputs in actuality. federal emissions laws brought horsepower era close , resulted in steady decline pontiac s engines. 1 holdout industry-wide slide super duty 455 engine of 1973–1974. available in firebird formula , trans models, rated @ 310 hp (230 kw) net after having issues passing epa emissions tests, camshaft changed old ra iii cam , change, came 290 hp (220 kw) net rating. engine pinnacle of pontiac engine development , strong performer included few race-specific features, such provisions dry-sump oiling. engine , legacy drive sd trans ams , formulas 1 of more, if not most, desirable pontiacs ever produced.

the non-traditional pontiac v8 engines 301 cubic inch , smaller displacement 265 cubic inch v8s. produced 1977 through 1981, these engines had distinction of being last v8s produced pontiac; gm merged various brands engines 1 collectively shared group in 1980, entitled general motors powertrain. interestingly, 301 had 4-inch (100 mm) bore , 3-inch (76 mm) stroke, identical vaunted chevrolet small-block engine , ford boss 302 engine.

pontiac engines not available in canada, however, replaced chevrolet engines of similar size , power, resulting in such interesting , unusual (at least american car fans) models beaumont sd-396 chevrolet big-block 396 cubic inch v8.

carburetors

pmd used carter 1-barrel carburetors many years, time of second generation v8 engines had switched 2-barrel offerings. these basis tri-power setups on engines.

the tri-power setup included 1 center carburetor idle control , 2 end carburetors did not contribute until throttle opened more half way. accomplished 2 ways, mechanically manual transmission models, , via vacuum-switch on automatics. went through various permutations factory installed option in 1957-1966.

pmd had square-bore 4-barrel @ time, rated @ lower power tri-power. carburetor later replaced quadrajet, spread bore. spread-bore refers difference in sizes between primaries , secondaries, using smaller primaries paired larger secondaries increased airflow @ wider throttle fuel delivery changes akin two-plus-four benefit of tri-power single carburetor. must understood q jet not thing gave top gto 400 engine , 428 h-o engines same h.p. 389 , 421. aside of displacement advantage new engine had redesigned cylinder heads different valve angles , larger ports. different valve angles allowed larger diameter intake , exhaust valves. there have been many test when tri-power set-up added 400 or 428 engine made more h.p. q-jet.

by end of muscle car era, quadrajet setup had become ubiquitous choice on pmd engines. quadrajet design continued until 1990 oldsmobile v8 applications, along added computer controls meet emissions , fuel economy standards.