What's The Difference Between The Pontiac 400 And The Chevrolet 400?

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In nan 1960s and 1970s, Chevrolet and Pontiac some offered a pushrod V8 motor pinch an advertised displacement of 400 cubic inches. Considering that some carmakers are (were?) sub-brands of genitor institution General Motors, 1 mightiness presume that these 2 engines stock a akin architecture aliases mightiness moreover beryllium nan same, but that's hardly nan case. The Chevy has a bore and changeable of 4.125 inches and 3.75 inches, respectively. Meanwhile, nan Pontiac has a 4.12-inch bore and 3.75-inch stroke. While that facet of nan 2 motors is admittedly astir identical, that's wherever nan similarities end.

Chevy's 400 cubic inch V8 debuted for nan 1970 exemplary twelvemonth and ran done 1980. It was importantly based connected nan small-block V8 that Chevy launched successful 1955, which powered much cars than immoderate different engine, ever. Chevy's 400 was besides 1 of nan largest small-block V8 engines until nan 427-cubic-inch LS7 came retired successful 2006.

The Chevrolet 400 was designed to supply other torque successful vehicles for illustration ample sedans, trucks, and early SUVs like the 1988 K5 Blazer. While it could beryllium modified for performance, Chevy's 400 ne'er made overmuch horsepower successful mill form. Fortunately, nan aforesaid isn't existent for Pontiac's 400, which powered galore of nan brand's iconic musculus cars and pony cars.

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Considered by galore gearheads to beryllium nan first musculus car and possibly moreover considered 1 of the champion musculus cars ever, Pontiac's GTO roared into showrooms successful 1964 pinch a brand-specific 389 cubic inch V8 nether nan hood. It's that nonstop motor which would get saturated retired somewhat to measurement 400 cubic inches for nan 1967 exemplary year. To beryllium sure, Pontiac installed nan 400 successful immoderate boring grocery-getter sedans and wagons, but it besides had a rambunctious Ram Air IV type that represented nan apex of powerfulness for this engine.  

In 1969, nan Ram Air IV made 345 horsepower successful nan Firebird and 370 horsepower successful nan larger GTO. This was an era erstwhile manufacturers utilized fantastical gross horsepower ratings — measured without exhaust aliases parasitic resistance from accessories for illustration an alternator — that couldn't beryllium replicated successful nan existent world. By contrast, immoderate musculus car fans declare that nan Pontiac 400 was really rated astatine little than its existent potential.

In 1970, Pontiac's don't-call-it-a-big-block 455-cubic-inch V8 dethroned nan Ram Air 400 arsenic nan top-dog motor action successful capacity machines for illustration nan GTO and Trans-Am, noted for the bird that Pontiac put connected its hood that looked for illustration a screaming chicken. Pontiac dropped nan 455 aft 1976, erstwhile again making nan 400 nan motor to covet successful "Smokey and nan Bandit"-era Trans-Ams (promoted arsenic a blase "6.6 Litre" displacement) until it excessively was discontinued successful 1979. By comparison, possibly nan champion point that tin beryllium said for Chevrolet's 400-cubic-inch small-block is that a 400 crankshaft successful a 350 artifact makes nan desirable 383 stroker, a basking rodding favourite that Chevy sells in crate motor shape to this day.