Editing AMC V8 engine (section)

== Gen-2 AMC short-deck V8 (1966–1969)<span class="anchor" id="2"></span><span class="anchor" id="1966"></span> ==
[[File:1967 AMC Marlin white with red interior 06.jpg|thumb|Engine bay of a 1967 [[AMC Marlin]] with a 4-barrel 343 Typhoon V8]]
[[File:1969 AMC AMX with bare engine block.jpg|thumb|Engine bay of a 1969 [[AMC AMX]] with a bare V8 block]]

The new-generation AMC V8 was introduced in 1966<ref>{{cite book |last=Glastonbury |first=Jim |title=Muscle Cars: Style, Power, and Performance |date=2016 |publisher=Book Sales |isbn=978-0-7858-3483-0 |page=220 |url= https://books.google.com/books?id=5qNEDwAAQBAJ&pg=PA220}}</ref> It is sometimes referred to as the "Gen-2" AMC V8. The first version was the completely new {{cvt|290|CID|L|1}} Typhoon V8 introduced in a special mid-1966 model year "Rogue" hardtop. Available in {{cvt|200|hp|kW PS|0}} two-barrel [[carburetor]] version or producing {{cvt|225|hp|kW PS|0}} with a four-barrel carburetor and high compression, the new engines utilized "thin-wall" casting technology and weighed only {{convert|540|lb|kg|0}}.<ref name="pm-may1966">{{cite magazine |last=Dunne |first=Jim |title=V8 for Rambler American |magazine=Popular Mechanics |volume=125 |issue=5 |page=60 |date=May 1966 |url= https://books.google.com/books?id=AdQDAAAAMBAJ&pg=PA70}}</ref> and produced in three displacements - between {{cvt|290|CID|L|1}}, {{cvt|343|CID|L|1}} and {{cvt|390|CID|L|1}} - until 1969.

All three engines share the same basic block design and external measurements; the different [[engine displacement|displacements]] are achieved through various bore and stroke combinations. 

Bore center measurement was kept the same as the Gen-1 V8 at {{cvt|4.75|in|mm|1}} so that boring equipment could be reused. Other than that, this engine is vastly different from the Gen-1 model. The Gen-1 engine is physically the size of a big-block Ford or GM engine, and is sometimes called a "big-block". The Gen-2 is closer to the physical size of U.S.-made small-block V8s except for the bore centers, which are the same as some big-block engines. The only parts shared between the 1966-67 Rambler V8 and 1966-91 AMV8 are the lower cam timing sprocket and the timing chain.{{cn|date=April 2021}}

The AMC V8 was not built by [[Ford Motor Company|Ford]] or anyone else although it bears an uncanny resemblance to the later Buick V8 engines (400, 430, 455).{{cn|date=April 2021}} It shares the same design employing a timing gear case that mounts both the distributor and oil pump. It also shares the same oiling scheme employing a single passage to feed both cam and crank from the right lifter bank by tangentially intersecting the cam bore instead of two drilled passages, one from the cam to crank and another from the crank to the right lifter bank. Some electrical parts (starter and distributor) were shared with Ford, and some models used [[Motorcraft]] (Ford) carburetors, but the balance of the engine design is unique.

The Gen-2 AMC V8 was first introduced at {{cvt|290|CID|L|1}} in 1966. It was used exclusively in the Rambler American model in the first year. The {{cvt|343|CID|L|1}} came out in 1967 and the AMX {{cvt|390|CID|L|1}} arrived in mid-1968. These engine blocks were unchanged through the 1969 model year.

The head used during this time was the so-called "rectangle port", named after its [[exhaust manifold|exhaust port]] shape. The 290 heads use smaller valves, {{cvt|1.787|in|mm|1}} intake and {{cvt|1.406|in|mm|1}} exhaust, corresponding with its small bore. The 343 and the AMX 390 use the same larger valve heads, {{cvt|2.025|in|mm|1}} intake and {{cvt|1.625|in|mm|1}} exhaust.

===290===<!-- This section is linked from [[AMC Gremlin]] -->
The base {{cvt|290|CID|L|1}} produced {{cvt|200|or|225|hp|kW|0}} with a two-barrel or four-barrel carburetor, respectively. It was built from the mid-1966 model year through the 1969 model year. It has a bore and stroke of {{cvt|3.75x3.28|in|mm|1}}. Only 623 cars were built in 1966 with the 290 engine. These engines were available in special [[Rambler American]] two-door Rogue models.<ref name="pm-may1966"/> The newly powered Rogue was available with either a three-speed automatic or a floor-mounted four-speed manual transmission and made the car "suitable for the Stoplight Grand Prix."<ref name="AmericanMuscleCars8"/>

=== 343 ===
The {{cvt|343|CID|L|1}} has a bore and stroke of {{cvt|4.08x3.28|in|mm|1}}. The basic 343/2V produced {{cvt|235|hp|kW PS|0}} and was built from 1967 through 1969. Output for the optional four-barrel carburetor version is {{cvt|280|hp|kW PS|0}} and produces {{cvt|365|lbft|Nm|0}} of torque (gross). This version has a 10.2:1 compression ratio.

=== AMX 390 ===
[[File:1968 AMC AMX yellow 390 auto md-er.jpg|thumb|right|The AMX 390 engine in a 1968 [[AMC AMX|AMX]]]]

The {{cvt|390|CID|L|1}} AMX engine had a bore and stroke of {{cvt|4.165x3.574|in|mm}}. It received heavier main bearing support webbing than the smaller AMC V8s, as well as a forged steel crankshaft and [[connecting rods]]. Forged cranks and rods were used for their known strength—there was inadequate time for testing cast parts for durability without delaying AMC's introduction schedule. Once forging dies were made it was not cost-effective to test cast parts due to the relatively low number of engines produced. The use of these stronger components was also continued with the production of 401 engines. This is an advantage of these AMC engines when used in heavy-duty and high-performance applications because they have no problems with their connecting rods breaking; unlike other domestic automakers' large displacement small block engines.{{cn|date=April 2021}} The Gen-2 AMX 390 produced {{cvt|315|hp|kW PS|0}} and was built in 1968 and 1969.