Editing Pontiac V8 engine (section)

==Ram Air==
The beginnings of Pontiac's iconic Ram Air dynasty began during the 1965 model year. The GTO's new hood scoop design, with the inlets centrally located and mounted above the carburetor, provided the opportunity for experimentation. Royal Pontiac developed the prototype of the package on their 1965 GTO drag car and Pontiac picked up the idea and in August 1965 Pontiac offered the new Fresh Air package to dealers consisting of the parts and instructions needed to make the hood scoop functional, including the metal tub to mount to the carburetors and rubber gasket to seal it to the underside of the hood. The Fresh Air package continued into the 1966 model year.

Around January 1966 Pontiac took the next step and began offering as a factory option the XS-code engine. It included a new camshaft with duration increased from 288/302 (No. 068) to 301/313 (No. 744) and a new valve spring package with dampers to positively control valve action. Valve lift stayed at just over 0.400-inch with 1.5:1-ratio rocker arms. The tri-power equipped XS-code 389 was shipped with the Ram Air pan in the trunk, and the dealer had to fit it and cut out the underside of the hood scoop to make it functional. The XS-code 389 was still rated at 360&nbsp;bhp at 5,200&nbsp;rpm, same as the more common WS-coded Tri-Power 389, but performance was noticeably improved on acceleration runs. Pontiac engine production records report that 190 XS-code 389 engines were built during the 1966 model year. Whether all were installed in GTOs is unknown.

None of Pontiac's Ram Air engines actually enjoyed any true ram air effect. The inlets were all well within the boundary layer that exists close to the surface, so all of these systems would more accurately be described as "outside air induction" systems, benefiting from the intake of cooler, and thus denser, outside air versus the comparatively hotter and less dense air under the car's hood.

===Ram Air (1967- mid year 1968)===
Simply called "Ram Air" by Pontiac<ref>{{Cite web|title=Directory Index: Pontiac/1967 Pontiac/1967_Pontiac_Performance_Brochure|url=http://www.oldcarbrochures.com/static/NA/Pontiac/1967%20Pontiac/1967_Pontiac_Performance_Brochure/dirindex.html|access-date=2021-11-17|website=www.oldcarbrochures.com}}</ref> it was the first in a series of engines available from Pontiac as regular production line options and officially called Ram Air. Hewing to GM's standing edict limiting engine size to 400 cu in for its midsize and smaller cars, the {{cvt|360|hp|0}} (underrated),{{Citation needed|date=December 2008}} the 400 cubic inch Ram Air V-8 was the most powerful and advanced option available in the 1967 GTO and Firebird. 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. It featured the "744" 301/313 camshaft, which offered more duration and overlap than the "HO". Along with the HO it also had Pontiac's famous cast-iron "headers", which were much better at reducing backpressure than the regular manifolds. The 670 heads were used until May 1967 when they were upgraded to become the "97" heads, which were then replaced late in the model year by the "997" heads which incorporated the upgrades of the "97" heads.

===Ram Air II (1968 1/2)===
The 1968 Ram Air II remained at 400 cu. in., again available only in the GTO and Firebird. It was factory rated at 366&nbsp;hp at 5,400&nbsp;rpm and 445&nbsp;lbs.ft. of torque at 3,800&nbsp;rpm in the GTO, and 340 HORSEPOWER at 5,300&nbsp;rpm and 430-lb.ft. of torque at 3,600&nbsp;rpm in the Firebird, with only a small throttle restrictor tab on the Firebird being different.{{citation needed|date=April 2021}} 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. The Ram Air II also incorporated the first computer-designed camshaft. This camshaft sported a 308-/320-degree duration with {{convert|0.47|in|mm|adj=on}} lift. This same camshaft was also used in Pontiac's 1969–1970 RA IV production cars. However, the RA II was limited to a 1.50:1 rocker ratio, while the RA IV used a 1.65:1 ratio, which yielded significantly greater total lift and, therefore, superior flow and power.{{citation needed|date=February 2018}}

=== 400 Ram Air (1969) / Ram Air (1970), aka Ram Air III ===
Often called the "Ram Air III", this engine was officially called the "400 Ram Air" for 1969 and then simply "Ram Air" for the 1970 model year. It would later become known colloquially as the "Ram Air III", though Pontiac never called it by that name. A 400 cubic inch ram air equipped V8, it was an option on the 1969-70 GTO and Firebird Formula. For the 1969 and 1970 model years it was the standard engine in both the Firebird Trans Am and the GTO Judge. It was the same engine as the '67-'68 400 HO<ref>{{Cite web|url=https://www.hemmings.com/stories/article/1968-pontiac-gto-3 |title=1968 Pontiac GTO |first=Matt |last=Litwin |date=August 2013 |access-date=2021-08-15 |website=Muscle Machines |via=www.hemmings.com}}</ref> but for 1969 and 1970 it included a driver-selectable outside air induction system on the GTO(it was a separate option on Firebird), with the hood vents opened and closed using a knob located under the dash, below and to the right of the steering wheel, its bracket labeled "RAM AIR". It used the "744" camshaft (301-313) in the earlier manual trans versions, later downgraded to the "068" version, and the 288/302 duration cam with automatic transmission. It was rated at {{cvt|366|bhp|0}} (gross) in the GTO version. Like previous generations of Ram Airs, it used Pontiac's special cast-iron "headers". It had 2-bolt main bearing caps in 1969, but went to a block similar to the Ram Air IV's in 1969 that was drilled for 4-bolt main bearing caps (but used a cast crank and cast rods). In 1970 the casting number #9799914 Ram Air 400 4-bolt main block also used the 4-bolt main caps on Ram Air applications.

===Ram Air IV (1969-1970)===
The Ram Air IV replaced the Ram Air II in 1969. It was called the Ram Air IV due to the planned use of four air inlets. Though production cars only got the two hood air inlets the name was retained.  All 1968–69 #9792506 Ram Air 400 blocks have 4-bolt caps. The Ram Air IV used the Ram Air II's camshaft but lift in the Ram Air IV was increased to {{cvt|0.52|in|mm}} thanks to the use of 1.65 ratio rocker arms (vs 1.50). The Ram Air IV heads had 1/8" taller intake ports, larger intake port volume with more airflow, yet shared the Ram Air II round exhaust ports. In addition, a shallower spherical-wedge combustion chamber moved the tuliped valve heads .040" closer to the piston at TDC, improving mixture draw considerably during the intake stroke. The Ram Air IV also used a lightweight aluminum intake-manifold that produced a weight savings of {{cvt|10|-|15|lb}}. From 1969 though 1970, the Ram Air IV was available in both A-Body (GTO, including Judge) and F-body (Firebird, including Trans Am) form. While production of 1969–70 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. Only 157 Ram Air IV Firebirds, including 55 Trans Ams, were built for 1969. For 1970 the Trans Am was the only Firebird available with the Ram Air IV, and 88 were produced during the abbreviated 1970 F-body production run. A total of 1,808 Ram Air IV production cars were built over its 2-year production. Pontiac continued using its round-port cylinder-head design for 1971-'72 on the 455 HO. However, compression ratios were cut dramatically, marking the beginning of the end of the muscle car era.

===Ram Air V===
Though never factory-installed in any car, the ultimate engine of the Ram Air line of engines was the tunnel-port Ram Air V. In 1969 [[Pontiac (automobile)|Pontiac]] created four versions of the Ram Air V engine: a {{cvt|303|cuin|L|1}} short deck version for [[Sports Car Club of America|SCCA]] [[Trans-Am Series|Trans-Am]] racing, a {{cvt|366|cuin|L|1}} variant for [[NASCAR]], a {{cvt|400|cuin|L|1}} version for street use in [[Pontiac GTO|GTOs]] and [[Pontiac Firebird|Firebirds]], as well as a {{cvt|428|cuin|L|1}} adaptation for [[drag racing]].<ref name="hotrod">{{Cite web|url=http://www.hotrod.com/articles/609ci-pontiac-ram-air-v-chief-stomp-em/|title=609ci Pontiac Ram Air V - Chief Stomp 'Em|date=2014-06-04|language=en-US|access-date=2016-07-29}}</ref> The cylinder head design is similar to the [[Ford FE engine|Ford FE]] tunnel-port head used in the [[Ford GT40|GT40]] and [[Can-Am]] series racing. So large are the intake ports that the pushrods run through the center of each port via pressed-in tubes, in addition to streamlined airfoils over the tubes themselves to improve port shape, and increase flow velocity. The 303 had shorter connecting rods, smaller {{cvt|2.5|in|mm}} journals and a solid lifter version of the Ram Air IV camshaft. It adopted a {{cvt|4.125|in|mm|1}} bore with a {{cvt|2.84|in|mm|1}} stroke, shared with the standard deck 303, for a displacement of {{cvt|303.63|cuin|cc|0}}. The short deck engine weighed about {{cvt|40|lb|kg}} less than the other variants and had an 8000&nbsp;rpm redline. Pontiac's SCCA Trans-Am program was promising, with race-ready engines producing {{cvt|475|hp|0}} to {{cvt|525|hp|0}}, however the series’ General Competition Rules required the manufacturer to produce no less than 250 vehicles with the 303. Plans were made to produce Firebirds and GTOs with advertised ratings of {{cvt|355|hp|0}} and {{cvt|375|hp|0}} respectively but concerns about emissions, the response of the automobile safety lobby, and the warranty implications of a high-revving street engine led to cancellation of the program.{{Why|How were these circumstances any different than for the special 302 cu in Boss Mustang and Z/28 Camaro engines built for the exact same reason (and successfully campaigned in Trans Am) or the Plymouth Barracuda AAR/Dodge Challenger T/A, which received specially modified 340 cu in small blocks with unique triple 2-bbl "Six Pack" configurations for Trans Am class racing.|date=April 2021}} {{citation needed|date=July 2016}} T

While the exact total number of Ram Air V engines produced is not positively known, only about 25 {{cvt|303|cuin|L|1}} engines were produced and about a dozen 428s and 366s. More {{cvt|400|cuin|L|1|adj=on}} engines were produced by Pontiac than the other versions - estimates range from 80 to 200 units. Some 400s were dealer installed.<ref name="hotrod"/>

Parts for Ram Air V engines are not readily available. The cylinder heads on the 400 CID version had an intake port volume of {{cvt|290|cc|2}}, nearly twice the size of a typical standard D-port Pontiac head - and flowed in the area of {{cvt|315|cuft/min}} at {{cvt|0.8|in|mm}} valve lift; in the realm of the NASCAR-dominating [[Chrysler Hemi engine|Chrysler 426 Hemi]].{{citation needed|date=April 2021}}