was rated 180hp (134kW) @ 4600rpgold necklace for teenage girl

It was rated 180hp (134kW) @ 4600rpm and 264lbft (358Nm) @ 2400rpm with a two-barrel carburetor, 200hp (149kW) @ 4600rpm and 278lbft (377Nm) @ 2800rpm with the four-barrel carburetor. Head bolts do not pull on the cylinder wall causing distortion. The premier SD 421 cylinder head was the late 1962-early 1963 casting #9771980 aka "980", featuring a larger 11.3cuin (185cc) intake port volume, flowing 230cuft/min (6.5m3/min) @ 28in (710mm). What if that one stud was not pressed in as deep as the rest machine shop says the stud is out a little compared to the rest could the p/r and valve push the stud back out when the valve bent or suspect this was already the case, Upstate New York, watching my New Yorker Rust, (You must log in or sign up to reply here. Not Valid With Any Other Sales OfferThe multi price discount allows you the opportunity to buy additional units of this part at a discounted price according to the published price schedule. All W72 equipped Trans Ams featured the "T/A 6.6" shaker decal. The 1958 370" engine and the 195960 389 version was named the "Tempest" V-8 and changed in 61 to the "Trophy" V8. As a result, it was remarkably free of teething problems. By early 1979, orders for the W72 package were being rejected by dealers as they supply had run dry. Made with a provision for dry sump oiling, it truly was a racing engine, detuned for use in passenger cars. The "455 HO" moniker took on a whole new meaning with the introduction of the 1971 model year; Intended as a low compression progression from the previous years Ram Air IV engine, all 1971 455 HO engines used a heavy duty 4 bolt main block, round port cylinder heads (casting #197; with 8.4: compression), "Ram Air" style exhaust manifolds, and a two-part aluminum intake manifold. Still, it was the strongest American engine offered that year. 301 4-barrel 'W72' or 'ESC' (170hp, 127kW) (with the 5th character of the VIN being a "W" for 1979-1980 and the 8th for 1981). The machinist's ball should measure 0.3125-inch in diameter. Ecommerce Solution by BigCommerce, Bulk Discounts for PUSHRODS, PONTIAC 326, 389, 421, 8.693" X 5/16 HEAT TREATED CHROME MOLY. Three two-barrel carburetors, 10.75:1 compression, 290hp (216kW) @ 5000rpm, 375lbft (508Nm) @ 2800rpm. - eBay Money Back Guarantee - opens in a new window or tab, - for PayPal Credit, opens in a new window or tab, Learn more about earning points with eBay Mastercard, - eBay Return policy - opens in a new tab or window, - eBay Money Back Guarantee - opens in a new tab or window. which was seen on the hood of the 1957 Daytona Grand National winning car driven by Cotton Owens. The 1972 455 HO was rated at 300hp (224kW) @ 4,000rpm and 415lbft (563Nm) @ 3,200rpm. [citation needed] It was the first engine that incorporated Pontiac's round-port head design in a production vehicle, however the intake port was the same as other D-port heads, leaving a head which exhaust port could nearly match the intake at high valve lifts. Note: Due to current supply issues normal delivery times are currently being delayed. The head design was incorporated from the earlier 1970's 350 Pontiac heads, and could satisfy emissions in all states except for high-altitude emissions states and California. designs, the SD-455 was a much improved engine. When fitted with other high-airflow components, it produced a good balance of low-end torque and higher-RPM power. The reason is the measurement is affected by the oil holes on the ends of the pushrods. Privacy Policy. They came up with a 269-cubic-inch (4.4L) L-head design. Its cast "670" heads had taller valve spring heights than the standard D-port heads, and the only 14-degree valve angle closed combustion chamber making these heads unique. On gaskets I always follow the recommendation of the gasket manufacturer. Some 400s were dealer installed. Pontiac differed from other GM Divisions and most other manufacturers in producing only a single small block V8, rather than adding a larger big block to its line-up. Along with the HO it also had Pontiac's famous cast-iron "headers", which were much better at reducing backpressure than the regular manifolds. i am looking into pricing another one. In 1969, Pontiac unveiled its Trans Am model Firebird, and since racing rules required engines of less than 5L (305.1cuin), Pontiac unveiled the 303 for racing models only, never available to the public. This was a completely stock car on loan from a private owner for the test. These .065" Wall Chrome moly pushrods are strong yet light, they're an excellent choice for most any high performance application. Generally, these are restricted to an adjustment range less than 0.025-inch, so the pushrod length must be very close to ideal. 455 (7.5) Buick Gran Sport, and 455 (7.5) Oldsmobile 442). Offer is only available at YEARONE.com, phone orders are not eligible. For 1959 the V8's stroke was increased to 3+34in (95.3mm), raising displacement to 389cuin (6.4L). JavaScript is disabled. The W72 was only available for a very short time, with the majority of 1979 model year W72 Firebirds ordered in late 1978. But the "Ram Air" 400 also mandated steep 4.33:1 gears(or 3.90:1 in Firebird), making the Quadra-Power 400 (400 HO) the top practical street engine option for most drivers. Pontiac 389 421 Pushrod Set 16 Each USA Made, {"modules":["unloadOptimization","bandwidthDetection"],"unloadOptimization":{"browsers":{"Firefox":true,"Chrome":true}},"bandwidthDetection":{"url":"https://ir.ebaystatic.com/cr/v/c1/thirtysevens.jpg","maxViews":4,"imgSize":37,"expiry":300000,"timeout":250}}. It was rated at 360hp @4300 RPM in the GTO and 370 @ 4600 RPM in the Grand Prix and other full-size Pontiacs. All 196869 #9792506 Ram Air 400 blocks have 4-bolt caps. Casting No. The concept car Pontiac Strato-Streak was used to introduce the V8 and in later years the engine was installed in Pontiac products. The 1971 455 HO was available in the Firebird (optional in Formula; standard in Trans Am), the GTO (standard with "The Judge" package), and the 2-door LeMans, LeMans T-37 (including GT-37), and LeMans Sport. Standard only for the Pontiac Bonneville was Pontiac's first-ever fuel injection system. Determining pushrod length is among the last custom settings accomplished when assembling a new engine. Compression ratio was a modest 8.00:1, with valve diameters of 1.781in (45.2mm) (intake) and 1+12in (38mm) (exhaust). No, it doesn't have to spin fast. Two four-barrel carburetors, 10.5:1 compression, 285hp (213kW) @ 5100rpm, 330lbft (447Nm) @ 2600rpm. Engines with an adjustable valvetrain like the small- and big-block Chevy are among the most challenged when it comes to setting pushrod length, so we'll use them as examples. HOT ROD and CAR AND DRIVER) were fitted with the Ram Air IV-spec camshaft and functional hood scoops - a fact that has been confirmed by several Pontiac sources. The four-barrel 400 was a popular performance option for many of Pontiac's cars. Pontiac began as a "companion make" to the Oakland division of the General Motors line of automobiles in 1926. The main innovation of the Pontiac engine was reverse-flow cooling and the stamped rocker-arm system, which had been devised by Pontiac engineer Clayton Leach in 1948. I believe that they may be saying that your pushrods might be "too long". Only 157 Ram Air IV Firebirds, including 55 Trans Ams, were built for 1969. While production of 196970 A-body Ram Air IV cars was low at just 1563 units(759 1969 GTOs including 302 Judges, and 804 1970 GTOs including 397 Judges) 1969 and 1970 model year F-body Ram Air IV cars were even rarer at just 245 total units produced. For 1969-1970 GTO the 400 HO included driver operable Ram Air induction and was renamed "400 Ram Air" for 1969 and just "Ram Air" for 1970. Both used a single two-barrel carburetor. Machine shop provided i believe when they went to positive valve seals and removed the hats. 1964-1967 Pontiac 326 V8 and 1964-1966 389 V8 High Strength Chrome-Moly Pushrod. The 455 HO package was only available to late model year Pontiac Firebird Trans Am's, and was mandatory with a 4-speed transmission. 389 and 1967 400 1:st design uses .315" dia. After the 1974 SD455 was dropped the 1975 Firebird's top performance engine was an 'L78' Pontiac 400cuin (6.6L). The Fresh Air package continued into the 1966 model year. In 1969, Pontiac also used a revised crankshaft out of a Pearlitic malleable-iron, although it still used the "N" casting letter. 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. The Ram Air IV used the Ram Air II's camshaft but lift in the Ram Air IV was increased to 0.52in (13mm) thanks to the use of 1.65 ratio rocker arms (vs 1.50). The engine was dubbed the TEMPEST V-8, a nickname it retained until the end of 1960. It was called the Ram Air IV due to the planned use of four air inlets. By 1965 and 1966 the same combinations would be rated at 338hp (252kW) for the 4bbl and the two Tri-Power versions would be rated at 356hp (265kW) and the H-O version at 376hp (280kW). He replaced the regular valve seals with positive valve seals and removed the caps on the springs. For competition engines, the ideal pushrod length will be the one that creates the least amount of travel across the valve tip. In short, a push rod is a push rod, and they will be fine. Price will be updated as you change quantities on the product page. ** Remember, at least $189.99 added to your cart earns you free shipping on eligible items **, https://s3.amazonaws.com/gearbox-yearone-com/part-images/ng6506/ng6506.png. in., again available only in the GTO and Firebird. This will require more precise measurements. Both Chevy and Ford had 427 cu in performance engines, so Pontiac simply referred to its 427 as a 428 to one-up them. It was the top-of-the-line engine unless one opted for the "Ram Air" V-8 derived from it. Place the ball in the cup and measure the overall length including the ball. Offer is not valid on previous purchases and cannot be combined with any other sale or promotion offers unless otherwise stated. This specific engine has stock valve train with bottle neck studs but poly locks for the preload adjustment. Pontiac's V8s share the same 6.625in (168.3mm) connecting rod length, with the exceptions of the later short deck 301, 265, and 303 Ram Air V. Most Pontiac V8s had an overall length (to the edge of the water pump pulley) of 28.25in (718mm), an overall width of 27in (690mm), and a height (not including air cleaner) of 31in (790mm). The cometic mls gaskets have been heat cycled 6-8 times now, is this something i should replace? Any commments would be greatly appreciated. Again, its bore was expanded, this time 0.03in (0.76mm) to 4.1525in (105.47mm). [19] The cylinder head design is similar to the Ford FE tunnel-port head used in the GT40 and Can-Am series racing. If the pushrod is too short, the mark will be toward the intake (inboard) side of the valve tip. Power ratings increased accordingly: Several dealer-installed camshafts were optional to increase power further to 317hp (236kW). It was rated at 250hp (186kW) with 8.6:1 compression and 260hp (194kW) at 10.25:1 compression. Now set the adjustable pushrod in place and adjust the rocker until there is zero lash. The Ram Air IV also used a lightweight aluminum intake-manifold that produced a weight savings of 1015lb (4.56.8kg). The standard head seen on an L78 400 Pontiac was the low compression 6x8 head, while the 6x4 head seen on the W72 had hardened valve seats for a higher RPM operating range, improved air flow, and higher compression. The short deck engine weighed about 40lb (18kg) less than the other variants and had an 8000 rpm redline. A higher-output four-barrel carburetor version was offered, called the 326 HO (High Output). The results showed Pontiac that an L-head simply couldn't compete with an overhead valve engine. like the earlier 1971-1972 motor, but it was not the same motor, and featured standard d-port heads with a very conservative camshaft. In 1970 the casting number #9799914 Ram Air 400 4-bolt main block also used the 4-bolt main caps on Ram Air applications. An evolution of the RA IV and H.O. i guess if there is no oil in the lifter the cup has bottomed out so the only thing to move is the valve right? Perhaps the most unusual variation of the Pontiac V8 was the 1961-63 Trophy 4, which was a 45-degree inclined 194.43cuin (3.2L) inline-4 created from the right bank of the 389 for the debut of the Tempest. In basic 2-barrel form it produced 290 horsepower and 428ft. pounds of torque in 1968. [citation needed]. One version of the engine featured camshafts driven off the front of the engine, another design had the cams driven by gears off the back of the engine. This resulted in a lightweight design weighing less than the Chevrolet small-block V-8. Haqts, caps, hoods, cups not sure what they are called they come down over the springs about a half inch like a hat. During 19511952, Pontiac had 23 287cuin (4.7L) V8-equipped 1953 model production prototypes running tests on the GM proving grounds. Hewing to GM's standing edict limiting engine size to 400 cu in for its midsize and smaller cars, the 360hp (268kW) (underrated),[citation needed] the 400 cubic inch Ram Air V-8 was the most powerful and advanced option available in the 1967 GTO and Firebird. The 1970 '455 HO' was a conventional "D" port engine. In 1967 the 421 was enlarged to 426.61cuin (7.0L) by increasing its bore to 4.12in (104.6mm). The combined thickness of the two washers is subtracted from the gross length to determine true pushrod length. Get superior 210 radius end pushrods for one low price! This new material had stronger alloys in the iron. Thus in March 1973 Pontiac eliminated a timing solenoid that gave full vacuum advance and disabled the EGR valve in high gear after a period of time that happened to exceed the running time of the EPA testing cycle. In 1968, there was also a 350 "HO" which had increased power with the addition of higher compression #18 heads (#17 and #46 were the most common 2-barrel heads), a four-barrel carburettor and matching intake that was also used on the 400 and 428 engines. 301 2-barrel (135hp, 101kW), (5th character of the, 301 4-barrel (150hp, 112kW), (5th character of the. For 1956 the V8 was bored out to 3.9375in (100.01mm), increasing displacement to 316.6cuin (5.2L). Assuming we are dealing a 5/16-inch cup on one end, the technique is called the "overall length measurement". Federal emissions standards and the drive towards "corporate" engines shared among all GM divisions led to the progressive demise of the Pontiac V8 through the late 1970s. All prices are in USD. 744) and a new valve spring package with dampers to positively control valve action. A higher-output version was offered, called the 326 HO (High Output). 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. The very modest cam, combined with a low-compression ratio of 8.4 (advertised) and 7.9:1 actual resulted in 290hp (216kW) SAE NET. Manufactured by Elgin Industries in the USA, Specially hardened for improved column stiffness, Alex's Parts- The smart choice in valve train part, Add on payment, Special Item Order Option, CHEVY, LS SERIES, Gen III, Vortec, LS1, 3, 6, L92, FORD, SMALL BLOCK 302 HO w/ E7, GT40P & GT40, FORD 239, 256, 262, 272, 292, 312 "Y" BLOCK, ROCKER ARM PARTS, ALIGNMENT GUIDE, FULCRUM, Valve Spring Cups, Use with Stock OD SBC Springs on Aftermarket Heads, Set of Sixteen Cups, Pushrod Guide Plates, BB Chevy Gen 5/6 w/ 3/8" Base Threads, Set of Eight, Valve Seats, 1.812" x 1.468" x .250", Universal, Set of Eight, 1.500" Stainless Steel Exh Valves, Vortec, LT1, Single Groove, Std Length .289" late SB Chevy, Set of Eight Exhaust Valves, *NEW* SB Ford, GT40P Drop In Beehive Valve Spring Kit, Max Output I .560" Lift, Vsk7i49s-MC, Hyd Flat Tappet, 7/16" Rocker Studs for use on Pontiac Engine Running Roller Rockers, PUSHRODS, SB CHEVY, 7.794" x 3/8 HEAT TREATED CHROME MOLY, STD, PUSHRODS, SB CHEVY, 7.894" x 3/8 HEAT TREATED CHROME MOLY, +.100", PUSHRODS, PONTIAC 326, 389, 421, 8.693" X 5/16 HEAT TREATED CHROME MOLY. While not related to the 400 W72, the concept was the same. Pontiac planned to produce the 1953 models with the V8, but Buick and Oldsmobile appealed to GM management and earned a 2-year delay. Hmm, pushrod length? for 1980, and the 8th being a "T" for 1981). Surprisingly, Mopar actually agreed and sent over several of the engineers that designed both the 392 and 426 Hemi. According to the June 2019 issue of Muscle car Review magazine, during dyno testing performed during that era, the National Hot Rod Association (NHRA) rated this Pontiac W72 400 T/A 6.6 engine at 260 to 280 net horsepower instead of the 220-hp rating published by Pontiac. Modified versions of this engine were extensively used in NASCAR stock car racing and drag racing competition. The engine came with 543797 (4-barrel) and 9770716 heads for the tri-power and special exhaust manifolds and a 7H cam with 292deg. Displacement began at 287-cubic-inch (4.7L) and grew as large as 455-cubic-inch (7.5L) by 1970. Copyright 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Not long before the model year introduction, Pontiac management decided that the entire line would be V8-powered. The 1981 rendition of this engine was officially called the 301-EC [EC standing for Electronic Controls] in the 1981 GM factory service manual, removing the need for a W72 option separately as it was now the standard motor, similar to how all W72 engines in 1979 were coded L78.[16]. Nevertheless, there appears in the October 72 issue of MOTOR TREND, a road test of a 1973 SD-455 Grand Am. aluminum V8 it had offered in the Tempest and replaced it with a small-bore version of the standard 389cuin (6.4L) Pontiac V8. Custom shaft-mount rocker assemblies are becoming more commonplace, and these systems place enhanced emphasis on pushrod length. of torque at 3,800 RPM in the GTO, and 340 HORSEPOWER at 5,300 RPM and 430-lb.ft. Later heads had actual pushrod guide plates and also used the hardened pushrods. Pontiac went to open-chambered heads in some 1967 models and all 68 and up to improve power, engine breathing and reduce emissions. Rotate the crank until the lifter is on the base circle of the cam. 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. but, i have a question when i tightened up the pushrod and added a half turn, the valve went down instead of the lifter is this normal? By 1979, Pontiac was no longer allowed to produce the 400 engine as emissions further tightened. Set up a rocker and pushrod assembly and rotate the engine through at least two full valve lift cycles. 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. Please Answer The Following To Purchase This Part: This Is A Configurable Part. From 1977 to 1981 there were 4 distinct 301 versions: For 1981 model year vehicles, the engine codes are the 8th digit of the VIN. Pricing and promotions may change at any time without prior notice. Most Pontiac engines were painted light blue. The 1969 HO 350 HO was equipped with the 400cuin (6.6L)'s large valve heads (# 48's) and the 400 HO camshaft and rated at 330hp (246kW). View cart for details. The 421 also marked the end of the option for a forged-steel crankshaft. The valve angle was reduced from 17 degrees to 14 degrees for better breathing. For more information, visit www.P65Warnings.ca.gov. This may have been propagated by the only authorized company that is licensed to reproduce these decals not including the "6.6 LITRE" in the Trans Am decal kits, and only including "T/A 6.6" with no extra cost. Engine block and cylinder heads were cast at Saginaw Metal Casting Operations then assembled at Tonawanda Engine before delivery to Pontiac Assembly for installation. Pontiac engineers tested their 269cuin (4.4L) V8 in 1949 or 1950 against an OHV Oldsmobile Rocket V8 303cuin (5.0L) downsized to 270cuin (4.4L). Free-flowing exhaust manifolds from the 400 Ram Air were used late in the model year. One of the key modifications over the standard 301 4-barrel was the 301 Turbo block. More 400cuin (6.6L) engines were produced by Pontiac than the other versions - estimates range from 80 to 200 units. The 421 SD became factory installed in 1962 and in 1963 a street version became available from the factory with a dual four-barrel or three two-barrel Tri-Power carburetion. Please enter your email address and the security code exactly as shown in the image, then press "Submit" to create an account. It would later became known colloquially as the "Ram Air III", though Pontiac never called it by that name. The W72 offered many improvements over the standard L78 400 Pontiac. The 400 remained in production through the 1978 model year, with 1979 cars receiving engines produced the previous year. Officially named the Quadra-Power 400 for 1967 and renamed 400 HO for 1968, the 400 HO was first offered for 1967 as the third engine in the GTO line after the automatic-only 400 2-barrel and the standard 400 4-barrel (the 400 HO would not be offered in the Firebird until the 1968 model year). PY Online Forums - Bringing the Pontiac Hobby Together. Pontiac successfully competed against more-expensive inline four-cylinder models with their inline flathead six-cylinder engines. To get an accurate measurement, the cylinder head and head gasket must be installed and with the valve springs in the cylinder being measured replaced with light-duty checking springs. The earlier 1975-78 blocks had metal shaved from the journals and bottom end as well as a decrease in the nickel content of the block in an attempt to decrease the overall weight of the vehicle to help alleviate emissions and cost. Neither casting was equipped with an exhaust crossover. In addition to the more refined cylinder heads, block casting reinforcements in the lifter galley and main bearing oil pan rail area, it had forged connecting rods with larger 716-inch-diameter (11mm) bolts. Factory heavy-duty high-pressure oil pump and eight-quart sump, four-bolt main bearing caps with Moraine aluminum bearings, and #1110976 dual-point distributor without vacuum advance. These pushrods are a two-piece design with internal threads with one full revolution of the pushrod tip equal to a 0.050-inch change in length. The engines feature a cast-iron block and head and two valves per cylinder. Pontiac offered this to the public as a streetable version of the 421 SD. The W72 also featured a camshaft with a higher duration, finer tuned 800cfm Rochester Quadrajet, insulated fuel line, larger 60PSI oil pump, chrome valve covers, a larger harmonic balancer, and the "T/A 6.6" Shaker decal. One way to make life easier on the valvetrain is to idealize its operating geometry. The 1979 Firebird model line was the last year for the Pontiac 400, and by this point not only was it required with the 4-speed manual transmission, it also required the WS6 Special Handling Package as mandatory equipment. Pricing and promotions may change at any time without prior notice. do i still add the half turn after snug or do these adjustments after it is running. Measuring a pushrod that combines both a ball tip and a cup requires the use of a machinist's ball. It produced 120hp (89kW) After 1981, the Pontiac V8 was replaced entirely by the GM "corporate" V8's from Chevrolet and Oldsmobile. Thanks for responses. It's actually pretty easy, and we'll show you how. in. It retained the 421's 4in (101.6mm) stroke and 3+14in (82.6mm) main journal. Given how late in the model year it was, Pontiac decided not to incur the costs of recertifying the SD-455 for other models other than the Firebird. Like the 326, it was offered in both 2-barrel and 4-barrel versions. The short-deck block and different intake ports also required the design of a new intake manifold. i am in the middle of installng new scorpion rollers on my 389 and it appears my p/r's will need to be .220" longer. Conversely, a pushrod that is too long positions the rocker tip too far outboard (exhaust side), forcing the roller tip potentially to travel off the edge of the valve tip. An HO version could be ordered in the GTO, as GM had lifted its restrictions on offering engines larger than 400cuin (6.6L) in mid-sized cars (resulting in the 454 (7.44) Chevrolet Chevelle, Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass. This is a limited time offer. Each pushrod will offer one inch of travel. This was the beginning of factory supplied performance items such as 4 bolt main bearings and windage trays to reduce friction from crankcase oil. Inspect the position of the mark and re-adjust the pushrod length until the witness mark is roughly 1/3rd of the distance toward the intake side from centerline. Boost was wastegate limited to 91psi (0.6210.069bar). The Pontiac 301 EC (Electronic Controls) version offered in 1981 produced 155hp (116kW) and 245lbft (332Nm), although it's rumoured that the actual output was closer to 170hp (127kW). Maximum RPM (high-RPM engine): over 8000 rpm, Engine weight: estimated 550lb (249kg) complete, Power: estimated 640hp (477kW) at 7500rpm, This page was last edited on 4 July 2022, at 06:04. Ultimately Pontiac produced only 295 1973 SD-455 Firebirds (252 Trans Am, 43 Formula). In 1977 the 400-cubic-inch (6.6L) T/A 6.6, (RPO code W72) was created to fulfil the performance engine gap in the Pontiac line-up. Sitemap | Is this common when going from standard stamped steel to billet rollers. Shown below are parts other customers have bought with. Also, the new cam was about .010 longer, end to end, than the old cam {nothing to do with pushrod length--just general info}. All Pontiac V8s from 1955 to 1959 were reverse cooled, known as the "gusher" cooling system. Initially marketed as a 287cuin (4.7L), it went on to be manufactured in displacements between 265cuin (4.3L) and 455cuin (7.5L) in carburated, fuel injected, and turbocharged versions. The crankshafts 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. The 301 had a bore and stroke of 4in 3in (101.6mm 76.2mm). [citation needed]. Pontiac's SCCA Trans-Am program was promising, with race-ready engines producing 475hp (354kW) to 525hp (391kW), however the series General Competition Rules required the manufacturer to produce no less than 250 vehicles with the 303.