Editing Pontiac V8 engine (section)

==Small-journal engines:1955-1981==
===287===
The V8 engine was introduced for the 1955 model year as the "Strato Streak". Not long before the model year introduction, Pontiac management decided that the entire line would be V8-powered. This was based on results of over 1 million test miles, which was unheard of at the time. The 287 was an "oversquare" engine with a [[bore (engine)|bore]] and [[stroke (engine)|stroke]] of {{cvt|3+3/4|×|3+1/4|in|mm|1}}, for a total displacement of {{cvt|287.2|cuin|L|1}} and a main bearing diameter of 2.5 inches. [[Compression ratio]] was a modest 8.00:1, with valve diameters of {{cvt|1.781|in|mm}} (intake) and {{cvt|1+1/2|in|mm}} (exhaust). It was rated {{cvt|180|hp|0}} at 4600&nbsp;rpm and {{cvt|264|lbft|0}} at 2400&nbsp;rpm with a two-barrel [[carburetor]], {{cvt|200|hp|0}} at 4600&nbsp;rpm and {{cvt|278|lbft|0}} at 2800&nbsp;rpm with the four-barrel carburetor.

===317===
For 1956 the V8 was bored out to {{cvt|3.9375|in|mm}}, increasing displacement to {{cvt|316.6|cuin|L|1}}. A factory 285HP version was built specifically for NASCAR competition, and soon offered as an optional engine in the following forms:

(with [[manual transmission]])
* Two-barrel carburetor, 7.9:1 compression, {{cvt|192|hp|0}} at 4400&nbsp;rpm, {{cvt|297|lbft|0}} at 2800&nbsp;rpm
* Four-barrel carburetor, 8.9:1 compression, {{cvt|216|hp|0}} at 4800&nbsp;rpm, {{cvt|315|lbft|0}} at 2800&nbsp;rpm
* Dual Four-Barrel carburetor, 10.0:1 compression, 285 hp at 5100&nbsp;rpm, 330 lbft at 3600&nbsp;rpm.<ref>{{Cite web| title=New strato-streak engine released | url=https://www.pontiacsafari.com/ServiceCraftsmanNews/56-02-February.pdf | archive-url=https://web.archive.org/web/20231202020450/https://www.pontiacsafari.com/ServiceCraftsmanNews/56-02-February.pdf | archive-date=2023-12-02}}</ref>

(with [[Hydramatic]] automatic )
* Two-barrel carburetor, 8.9:1 compression, {{cvt|205|hp|0}} at 4600&nbsp;rpm, {{cvt|294|lbft|0}} at 2600&nbsp;rpm
* Four-barrel carburetor, 8.9:1 compression, {{cvt|227|hp|0}} at 4800&nbsp;rpm, {{cvt|312|lbft|0}} at 3000&nbsp;rpm
* Two four-barrel carburetors, 10.0:1 compression, {{cvt|285|hp|0}} at 5100&nbsp;rpm, {{cvt|330|lbft|0}} at 3600&nbsp;rpm.

===347===
[[Image:Pontiac Tripower.jpg|thumb|250px|Pontiac V8 engine with triple two-barrel [[Tri-Power]] carburetor setup]]

For 1957 the V8's stroke was increased to {{cvt|3.5625|in|mm}}, for a displacement of {{cvt|347|cuin|L|1}} and the main bearing size was increased to 2.625. For the first time, Pontiac offered '''[[Tri power|Tri-Power]]''', three two-barrel carburetors with a sequential linkage (replacing the previous dual-quad set-up). Power ratings increased with the increase in displacement and compression ratio:

(with manual transmission)
* Two-barrel carburetor, 8.5:1 compression, {{cvt|227|hp|0}} at 4600&nbsp;rpm, {{cvt|333|lbft|0}} at 2300&nbsp;rpm
* Four-barrel carburetor, 10:1 compression, {{cvt|244|hp|0}} at 4800&nbsp;rpm, {{cvt|350|lbft|0}} at 2600&nbsp;rpm

(with [[Hydramatic]])
* Two-barrel carburetor, 10.0:1 compression, {{cvt|244|hp|0}} at 4800&nbsp;rpm, {{cvt|350|lbft|0}} at 2600&nbsp;rpm
* Four-barrel carburetor, 10.25:1 compression, {{cvt|270|hp|0}} at 4800&nbsp;rpm, {{cvt|359|lbft|0}} at 2900&nbsp;rpm
* Three two-barrel carburetors, 10.75:1 compression, {{cvt|290|hp|0}} at 5000&nbsp;rpm, {{cvt|375|lbft|0}} at 2800&nbsp;rpm.

Several dealer-installed [[camshaft]]s were optional to increase power further to {{cvt|317|hp|0}}. which was seen on the hood of the 1957 Daytona Grand National winning car driven by Cotton Owens.

Standard only for the [[Pontiac Bonneville]] was Pontiac's first-ever [[fuel injection]] system. A mechanical system built by [[Rochester Products Division|Rochester]], it was similar in principle, but not identical, to a contemporary system offered as an option on the Chevrolet Corvette. Pontiac did not release official power ratings for this engine, saying only that it had more than {{cvt|300|hp|kW|0}}. Contemporary road tests suggest that it was actually somewhat inferior to the Tri-Power engines, although it did have better [[Fuel economy in automobiles|fuel economy]]. Only 630 Bonnevilles were produced for 1957, all of them fuel-injected.

===370===
For 1958 the V8's bore was increased again to {{cvt|4+1/16|in|mm|1}}, increasing displacement to {{cvt|369.4|cuin|L|1}}. The engine was dubbed the TEMPEST V-8, a nickname it retained until the end of 1960.

The fuel-injected engine became an option on any Pontiac model, carrying a staggering price tag of $500 (almost 15% of the car's base price). It was rated at {{cvt|310|hp|0}} at 4800&nbsp;rpm and {{cvt|400|lbft|0}} at 3,000&nbsp;rpm on 10.5:1 compression. Only about 400 were produced before the fuel injection system was quietly dropped.

===389===
[[File:1960 Pontiac Venture engine - 389 cid V8 (14115314547).jpg|thumb|{{cvt|389|cid|L|1}} dual quad engine in a 1960 [[Pontiac Ventura]]]]

For 1959 the V8's [[Stroke (engine)|stroke]] was increased to {{cvt|3+3/4|in|mm|1}}, raising [[Engine displacement|displacement]] to {{cvt|389|cuin|L|1}} and the [[main bearing]] size was increased to 3.00 inches. The large increase in the main bearing size was due to replacing the forged crankshafts for all engines except the SD racing versions with the introduction of an "Armasteel" cast steel crankshaft;<ref>{{Cite web |title=Pontiac V-8 Crankshafts |url=http://www.pontiacpower.org/PontiacCranks.htm |access-date=2025-01-28 |website=www.pontiacpower.org}}</ref> and the engineers being very conservative in how strong the cast crankshaft would prove to be. The "Armasteel" cast crankshaft was the first cast crankshaft introduced by any of the Detroit automakers and the standard hardened cast-iron crankshaft used throughout the entire Pontiac V-8 line until 1967. "Armasteel" was a trademark of pearlitic [[malleable iron]] developed by GM's [[Saginaw Metal Casting Operations]] around 1936, which was referred to as "locking ball" cast-iron, as opposed to the "flaking" type found in other engines. In 1967, Pontiac moved on to a technologically simpler [[Ductile iron|nodular cast iron]] (invented in late 1940s) crankshaft, which they continued to use until the Pontiac V8 engine was discontinued in 1982.The SD racing program was the source of factory supplied performance items such as 4 bolt main bearing caps and [[windage]] trays to reduce [[friction]] from [[crankcase]] [[Motor oil|oil]]. The 389 would remain the standard Pontiac [[V8 engine]] through 1966, offered in a bewildering variety of outputs ranging from {{cvt|215|to|368|hp|kW|0}}. The 389 was the standard engine for the [[Pontiac Grand Prix]] and [[Pontiac Bonneville]] and installed in the [[Pontiac GTO]] through 1966. Beginning in 1961 the Pontiac V-8 (389 and 421) was dubbed the '''Trophy V-8''', due to its many victories in racing.

====Trophy 4====
Perhaps the most unusual variation of the Pontiac V8 was the 1961-63 ''[[Pontiac Trophy 4 engine|Trophy 4]]'', which was a 45-degree inclined {{cvt|194.43|cuin|L|1}} [[inline-4]] created from the right bank of the 389 for the debut of the [[Pontiac Tempest|Tempest]]. With an identical bore and stroke of {{cvt|4+1/16|in|mm|1}} and {{cvt|3+3/4|in|mm|1}} it was precisely half the displacement of the 389 and shared numerous parts with the V8,<ref name=hemmings>[https://www.hemmings.com/magazine/hmn/2010/08/1961--63-Pontiac-Trophy-4/3632031.html 1961-'63 Pontiac Trophy 4, ''Hemmings Motor News'' August, 2010]</ref> yet weighed considerably more than half as the engine lower half and block casting were not simply divided down the middle.

==={{anchor|326|336}} 326/336===
[[File:1967 326 c.i. pontiac firebird engine.jpg|thumb|Pontiac 326 engine in 1967 Firebird]]
In 1963 Pontiac dropped the Buick division built [[Buick V8 engine#215|215 cu. in. aluminum V8]] it had offered in the [[Pontiac Tempest|Tempest]] and replaced it with a small-bore version of the standard {{cvt|389|cuin|L|1}} Pontiac V8. It shared the 389's {{cvt|3+3/4|in|mm|1}} stroke, but its bore was {{cvt|3.78|in|mm|1}} for a displacement of {{cvt|336.66|CID|L|1}}. It was rated at {{cvt|250|hp|0}} with 8.6:1 compression and {{cvt|260|hp|kW|0}} at 10.25:1 compression. Both used a single two-barrel carburetor. In 1964 when the new "A" body intermediates came out there was a new corporate (GM) engine size limitation to anything less than {{cvt|330|cuin|L|1}}. and so the 326 bore size was reduced to {{cvt|3.72|in|mm|1}}, giving a true {{cvt|326.06|cuin|L|1}}. The 326 subsequently became the optional V8 engine for Tempests, and later the [[Pontiac Firebird]], through 1967 and maintained the 17 degree cylinder head valve angle for its entire production run.

A higher-output four-barrel carburetor version was offered, called the 326 HO (High Output). With higher compression and dual exhaust it produced {{cvt|280|hp|kW|0}} for 1963–1964, and {{cvt|285|hp|kW|0}} for 1965 through 1967, its final year.

===400===
[[File:Pontiac 400ci V8 in 1976 Trans Am 50th Anniversary.jpg|thumb|A L78 400 4bbl engine in a 1976 Y82 Limited Edition [[Pontiac Firebird#1976|Trans Am]] ]]
For 1967, Pontiac retired the {{cvt|389|cuin|L|1}} and replaced it with the 400&nbsp;cu&nbsp;in ({{cvt|399.95|cuin|L|1|disp=out}}), a 389 [[bore (engine)|bored]]-out by +{{cvt|0.06|in|mm}} to {{cvt|4.12|in|mm|1}} and retaining its [[stroke (engine)|stroke]] of {{cvt|3+3/4|in|mm|1}}. The 400 remained in production through the 1978 [[model year]], with 1979 cars receiving engines produced the previous year.

In basic 2-barrel form it produced 290 horsepower and 428&nbsp;ft. pounds of torque in 1968.<ref name=400specs>{{Cite web|url=https://itstillruns.com/pontiac-400-specs-7621192.html|title=Pontiac 400 Specs|website=It Still Runs}}</ref> This was the engine installed in the [[Pontiac Executive]] line of large cars<ref>{{Cite web|url=https://www.automobile-catalog.com/car/1969/2792405/pontiac_catalina_hardtop_coupe_400_v-8_2-bbl_turbo_hydra-matic.html|title=Detailed specs review of 1969 Pontiac Catalina Hardtop Coupe 400 V-8 2-bbl Turbo Hydra-Matic offered since September 1968 for North America|website=www.automobile-catalog.com}}</ref> and its largest station wagon, the [[Pontiac Safari]].

In 1967, the [[cylinder head]] design was improved for the 400 4-barrel engine. The [[Angle seat piston valve|valve angle]] was reduced from 20 degrees to 14 degrees for better breathing. 1967 was the last year for closed-chambered heads. The "670" head was a 1967-only [[casting]], and the only PMD head to have a closed chamber with the new 14 degree valve angle. The 400 2-barrel and big car AFB 4 bbl kept the 20 degree valve angles for '67; starting in '68 all Pontiac V8s went to the 14 degree valve angle. Pontiac went to open-chambered heads in some 1967 models and all 68 and up to improve power, engine breathing and reduce [[Exhaust gas|emissions]]. The valve size increased as well, to {{cvt|2.11|in|1}} intake and {{cvt|1.77|in|1}} [[exhaust valve]]s on high-performance heads. Low-performance and two-barrel applications, the standard engine in [[Full-size car|full-sized]] Pontiacs, got {{cvt|1.96|in|1}} [[intake]] and {{cvt|1.66|in|1}} exhaust valves and pressed in [[rocker arm]] studs.

In 1975, to assist in meeting CAFE emissions standards, Pontiac drastically modified the structure and metallurgy of the 400 blocks being produced. The 2bbl option was no longer available, and the sole 400 available for all model lines became the L78 400 with a 4bbl Rochester Quadrajet. This 400 engine was relegated to only produce 185&nbsp;hp (or less depending on application) for the remainder of its production. These blocks were cast from 1975 through 1977, and were last used in 1978 model year vehicles. The block had metal shaved from the inner journals, and was made with a reduced nickel content to reduce weight from the completed engine with the goal of making the engine lighter, which would in turn reduce the overall weight of the vehicle, alleviating the emissions it produced. These blocks were denoted with casting numbers starting with 500, such as the "500557" blocks found in 1975-78 Firebirds. Pontiac did re-introduce the older, more durable block but the 400 no longer could meet the tightening emissions requirements, and block casting ceased in 1977. These stronger cast blocks were assembled and stockpiled for the 1978 and 1979 Firebirds equipped with the W72 Performance Package.<ref>{{Cite web|url=https://www.motortrend.com/how-to/picking-a-pontiac-400-or-455-block-for-performance-use/|title=Picking a Pontiac 400 or 455 Block for Performance Use|date=April 13, 2016|website=MotorTrend}}</ref>

The four-barrel 400 was a popular performance option for many of Pontiac's cars. When fitted with other high-[[airflow]] components, it produced a good balance of low-end [[Torque#Machine torque|torque]] and higher-RPM power. In the 1968 Pontiac GTO it was given a 10.75:1 compression ratio and tuned to deliver 360 horsepower and 445 foot-pounds of torque.<ref name=400specs/>

===350===
In 1968 the 326 was replaced by the similarly 389-derived 350, which used a {{cvt|3+7/8|in|mm|1}} bore and {{cvt|3+3/4|in|mm|1}} stroke for a total displacement of {{cvt|353.8|cuin|cc|0}}. Like the 326, it was offered in both 2-barrel and 4-barrel versions. In 1968, a {{cvt|320|hp|0}} HO option was offered in the Tempest and Firebird. The 1969 HO 350 HO was equipped with the {{cvt|400|cuin|L|1}}'s large valve heads (# 48's) and the 400 HO camshaft and rated at {{cvt|330|hp|0}}. In 1974 it was used in the GTO and was rated at {{cvt|200|hp|0}} ([[Horsepower#SAE net power|net]]).

Applications:
* 1968-1977 [[Pontiac Firebird]]
* 1968-1977 [[Pontiac LeMans]]
* 1968-1981 [[Pontiac Parisienne]]
* 1968-1970 [[Pontiac Tempest]]
* 1969 [[Pontiac Custom S]]
* 1970-1977 [[Pontiac Catalina]]
* 1972-1975 [[Pontiac Ventura]]
* 1973-1977 [[Pontiac Grand Prix]]
* 1974 [[Pontiac GTO]]
* 1978 [[Pontiac Grand Safari]]

===303===
In 1969, Pontiac unveiled its Trans Am model Firebird, and since racing rules required engines of less than {{cvt|5|L|CID|1}}, Pontiac unveiled the 303 for racing models only, never available to the public. Bore and stroke were {{cvt|4.125|x|2.84|in|1}} {{cvt|303.63|CID|cc|0}}. It was rated at {{cvt|475|hp|0}}.

===301===
The {{cvt|4942|cc|CID L cc|1|adj=ri0|order=out}} 301 was offered from 1977 to 1981 and also installed in other GM cars during those years. The 301 had a bore and stroke of {{cvt|4x3|in|mm|1}}. Based in part on designs for the "short deck" {{cvt|303|cuin|L|1}} engine designed for the 1970 racing season, it had a shorter deck than the big V8, and used thin-wall castings to reduce weight. The [[crankshaft]]s were also unique in the fact that they featured only two counter weights instead of the usual five and also featured lightened connecting rod journals. This resulted in a lightweight design weighing less than the [[Chevrolet Small-Block engine|Chevrolet small-block V-8]]. Power output ranged from {{cvt|135|hp|kW|0}} to {{cvt|170|hp|kW|0}}. The heads were a new design featuring siamesed intake ports. The short-deck block and different intake ports also required the design of a new intake manifold. The Pontiac 301 EC (Electronic Controls) version offered in 1981 produced {{cvt|155|hp|kW|0}} and {{cvt|245|lbft|Nm|0}}, although it is rumoured that the actual output was closer to {{cvt|170|hp|kW|0}}. Although it is much different from the original 1955-vintage Pontiac V-8 powerplant, the 301 has the distinction of being the last true Pontiac V-8 engine, as Pontiac ceased production of these engines effective April 1, 1981.

From 1977 to 1981 there were 4 distinct 301 versions:
* 301 2-barrel ({{cvt|135|hp|0|disp=comma}}), (5th character of the [[VIN]] is a "Y" for 1977–1979).
* 301 4-barrel ({{cvt|150|hp|0|disp=comma}}), (5th character of the [[VIN]] is a "W" for 1978–1980, and the 8th for 1981).
* 301 4-barrel 'W72' or 'ESC' ({{cvt|170|hp|0|disp=comma}}) (with the 5th character of the VIN being a "W" for 1979-1980 and the 8th for 1981).
* 301 Turbo ({{cvt|210|hp|0|disp=comma}}), (with the 5th VIN character being a "T". for 1980, and the 8th being a "T" for 1981).

For 1981 model year vehicles, the engine codes are the 8th digit of the VIN. The 2-barrel version was last offered in 1979. The 4-barrel version was available from 1978 to 1981 and the Turbo version was limited to the 1980 and 1981 model year, however, it was originally intended to be available for the 3rd generation Firebird before its cancellation by GM.

====301 Turbo====
{{See also|Pontiac 301 Turbo}}
The 301 Turbo was unique since it had a beefier block than the 1977–79 versions (which carried on in the non-turbo versions in 1980 and 1981), a very mild camshaft with {{cvt|0.35|in|mm}} lift and 250 degrees gross duration, a {{cvt|60|psi|bar}} oil pump to ensure adequate oil to the oil-cooled [[Garrett AiResearch|Garrett]] TBO-305 Turbocharger, a rolled fillet crankshaft, a fully baffled oil pan, and a specific {{cvt|800|cuft/min|lk=in}} Quadrajet carburetor. This had extra-rich "DX" secondary metering rods and a remote vacuum source for the primary metering rod enrichment circuit to allow the Power Enrichment Vacuum Regulator (PEVR) to release the primary metering rods to move to the up position (enrichment) anytime during boosted conditions. This was to ensure there was enough fuel to cool the cast offset dished pistons. Boost was wastegate limited to {{cvt|9|+/-|1|psi|bar}}.

The 301 Turbo package mandated air conditioning, the THM350 (sometimes referred to as the CBC350 in various literature) non-lockup automatic transmission (THM350C lockup in 1981 Trans Ams), and 3.08 rear axle gearing. The 1980 301 [[Turbocharger|Turbo]] was rated at {{cvt|210|hp|kW|0}} at 4400&nbsp;rpm and {{cvt|345|lbft|Nm|0}} at 2800&nbsp;rpm. The 1981 301 Turbo gained the electronic controls with an O<sub>2</sub> sensor, feedback ECM and E4ME [[Quadrajet]] providing a slight reduction in output to {{cvt|205|hp|kW|0}} and {{cvt|340|lbft|Nm|0}}; however, these revisions did allow it to meet California emissions standards (The 1980 version did not). The 301 Turbo was limited to Trans Am and Formula Firebird production only.

==== 301: Naturally Aspirated ====
* 1977-1981 [[Pontiac Bonneville]]
* 1977-1981 [[Pontiac Catalina]]
* 1977-1981 [[Pontiac Firebird]]
* 1977-1981 [[Pontiac Grand Prix]]
* 1977-1981 [[Pontiac LeMans]]
* 1977-1981 [[Pontiac Parisienne]]
* 1978-1980 [[Pontiac Grand Am]]
* 1978-1981 [[Buick Century]] / [[Buick Regal|Regal]] / [[Buick LeSabre|LeSabre]]

301:Turbo
* 1980-1981 [[Pontiac Firebird]] Formula / Trans Am

===265===
Based on the same short-deck as the 301, the "LS5" {{cvt|265.1|cuin|L|1}} was offered only in 1980 and 1981. It could only be ordered with a [[Turbo-Hydramatic#THM200|TH200]] automatic transmission and a 2bbl configuration. It was implemented as further development of a cost-effective, more fuel efficient V8 derivative of the 301 V8 for the CAFE requirements. It featured a smaller bore of {{cvt|3+3/4|in|mm|1}} coupled with the same {{cvt|3|in|mm|1}} stroke of the 301 (same bore and stroke used by Chevrolet when the first small block motor was introduced in 1955). It produced {{cvt|120|hp|0}} After 1981, the Pontiac V8 was replaced entirely by the GM "corporate" V8's from Chevrolet and Oldsmobile.

==== Applications ====
* 1980-1981 [[Pontiac Bonneville]]
* 1980-1981 [[Pontiac Catalina]]
* 1980-1981 [[Pontiac Firebird]]
* 1980-1981 [[Pontiac Grand Prix]]
* 1980-1981 [[Pontiac LeMans]]
* 1980-1981 [[Pontiac Parisienne]]
* 1980-1981 [[Buick Century]]
* 1980-1981 [[Buick Regal]]
* 1980 [[Oldsmobile 88]]