AMC Engine Specifications
Engine Specs
Engine Applications
Torque Specs
Crank/Rod Specs
Valve/Cam Specs
Piston/Ring Specs
1974 Engine Specs
1974 Performance Chart
Capacities Chart
Visit AMTech - Frank Swygert has collected engine build date code information, general engine information, and other useful technical info.
AMC Flywheel Information
1977-79 4 cylinder (AMC) 325-0437
1967-71 6 cylinder 317-2415
1972-79 6 cylinder 321-2623
1967-69 290 317-9069
1970-71 304 auto 319-6927
1972-78 304 3 speed 321-2651
1979 304 323-3955
1967-69 343 318-1609
1970-71 360 319-6929
1972-74 360 321-2653
1968-69 390 319-1662
1970 390 319-6929
1971 401 321-0496
1972-74 401 with 4 speed 321-2655
There are THREE distinctly different versions of the flywheel with part #3197219. If you have one of these flywheels, and you want to follow along with the description that follows, place your flywheel flat on the bench with the casting number facing up and at 12:00. (like you're reading a clock)

Version #1: #3197219-C
Crankshaft flange recess measurement: 4.500"
Counterweight position: at 7:30
Known to be out of a dead stock 1970 390 4-speed car.

Version #2: #3197219-C
Crankshaft flange recess measurement: 4.500"
Counterweight position: at 4:30
Known to be out of a dead stock 1970 360 4-speed car.

Version #3: #3197219 Does not have the "-C" after the casting number, but does have "E-25" (or other letter/number combo) cast in just above the counterweight.
Crankshaft flange recess measurement: 4.650 (approx. 5/32" larger than the above two versions)
Counterweight position: 9:30
Exact application: unknown. Believed to be out of a 72/up 360 or 401 (304's do not have a counterweight)

All cast-in counterweights are one square inch, with the exception of version #3 which is 1/4" shorter. (length 1", width 1", depth 3/4")

Thanks to: Tony Zamisch California Classic AMC, Inc., Aerolite Mfg. Co. (619) 423-0364, www.amx-perience.com

If you find any errors or omissions, please email me.

AMC "Small Block" V8 Engines
by Dave Crooks (courtesy of the AMX Files)
The AMC small block was first introduced in 1966. All six engine sizes (290 304 343 360 390 401) share the same basic block design. The different displacements are achieved by different bore and stroke combinations. All blocks share the same external measurements and thus can be swapped easily. Contrary to a popular myth the AMC V8's were not made by Ford or anyone else. They did make use of some Motorola electrical parts (Alternator, Starter etc) like the Fords, but the engine itself is all AMC.

1966-1969 (290, 343, 390)
The AMC small block was first introduced as a 290 in 1966. The 343 came out in 1967 and the "AMX 390" arrived in 1968. These engine blocks were unchanged until the end of 69. AMC block alloy contain a higher percentage of nickel than other brand engines. In addition to the largest bore and stroke, the 390 motor also got heavier main bearing support webbing and a forged steel crankshaft and connecting rods. The head used during this time, are the so-called rectangle port heads, named after their exhaust port shape. The 290 heads use smaller valves (1.787 intake, 1.406 exhaust) in order to prevent problems with the small bore. The 343 and 390 used the SAME, larger valve head (2.025 intake, 1.625 exhaust). You can swap the large valve heads onto a 290 but will need to notch the top of the cylinder bore to prevent the valves hitting, and will probably need different pistons as well. I don't think it's worth it though, the 290 works better with the smaller valves. The large valves are so close to the cylinder wall (on a 290) that they are shrouded by it and will actually flow less than the smaller valves.

1970 and Later (304, 360, 390, 401)
AMC heads make their engines extremely competitive if not superior to other small block engines. In 1970 all three blocks grew in deck height and the strokes were increased on the 290 and 343. The 290 became the 304, and the 343 became the 360. For some reason, however, the 390 remained a 390 in 1970. It wasn't until 71 that the 390 was stroked to the 401. Like the 390, the 401's crankshaft and connecting rods are forged steel. The other change in 70 was the switch to the dog leg heads (again named after the exhaust port shape). These heads are reported to flow 50% better on the exhaust side than the rectangle port heads and are thus the best for performance. There are two reasons for the flow increase: Firstly the area of the port is larger, due to the dog leg. Secondly the shape of the port floor was changed from a concave to a convex curve. The concave floor tended to bend the exhaust flow upwards which caused turbulence when the flow was forced to go down into the exhaust manifolds. By switching to a concave floor the curvature of the flow starts in the head and proceeds much more smoothly into the exhaust manifold resulting in less turbulence and better flow. As before there were two versions, a small valve one for the 304 and a large valve one for the 360/390/401. Again, like the 290, unless you have an extremely radical 304, you're probably best to stick with the small valve head on the 304. The late model 304 head is a good option for the early 290's but there are a few other things to consider, which are discussed later.

Production Changes

Throughout the lives of the heads there have been some changes made, mostly exact valve sizes, and chamber volumes. In general the 70 and earlier heads have about 51cc chambers and run around 10.2:1 compression. Some of the early (pre 68) heads had 53-54 cc chambers for 9:1, the later heads (71 and up) had about 58cc, which gave 8.0-8.5:1 ratio's when combined with the dished pistons used at the time. Using these late heads with the earlier flat top pistons will result in a compression ratio of about 9.5:1. In addition to chamber and compression ratio's some small changes in valve size were made. For example the exhaust went from 1.625 to 1.68 in the early 70's. These changes in valve size are pretty subtle and most drivers would never notice them. In any event you can get your heads machined to take the larger valves if you want, there's plenty of room to do it. You can even put the 343/360/390/401 valves in the 290/304 heads, although this is a bit risky as the castings are a bit thinner on the small valve heads and you run the risk of cracking a head if you open it up too much.

Rocker Arm Assembly
A minor change was made to the rocker arm assembly in 1973. Earlier heads used a round rocker arm pivot. This allowed the rocker some freedom to rotate. The rotation was limited by the width of the push rod slot. Later rocker arms used a cylindrical pivot. This pivot has a bridge which joins the intake and exhaust together maintaining proper alignment.

Swapping Heads
You can swap heads around pretty easily between these different engines. The 343 heads swap with the 68/69 390 heads, the 70-390, 360, and 401 heads swap. If you want to swap across the 1970 deck height change, you have to watch two things. The early block used 7/16 head bolts where the later used 1/2, and the center intake manifold bolts were re-located. To swap the late heads to a early engine you need a step dowel to ensure the heads are centered properly and you need to file the center manifold bolt holes to re-align the holes. Note that you can't escape the filing by swapping the late manifold onto the early engine because of the deck height difference. To swap a late model intake onto an early block you need to have the gasket face of the manifold machined down to compensate for the different deck height.

Group 19 - AMC high-performance parts were second to none
Muscle Car Review magazine, July 1990
by Barbara Hillick

When anyone mentions that they collect AMC musclecars, the common response is laughter from Chevy, Ford or Mopar owners. After all, Rambler had built an image through the years based on economy and reliability. When 1968 rolled around, AMC finally gave other performance cars more serious competition with the AMX and Javelin. When introduced in 1969, the SC/Rambler ran a 14.3 quarter straight off the showroom floor. Finally, with the introduction of the Rebel Machine in 1970 and the SC/36O in 1971, AMC showed that it had more than economy on its mind.

The basis for all performance cars is the parts available to make the cars stand out from the crowd. Parts like the Cross Ram were available for Chevy and Ford owners. Mopar owners had the Hemi engine, Six Packs, and a few other items to make their cars move on down the road. Somehow, no one seems to think of AMC as having performance parts. That's where they're wrong!

AMC took its first step into the performance market in 1966 when it introduced a totally new engine. This eight-cylinder 290 engine offered all kinds of performance possibilities to AMC owners when it was offered in a total of 625 cars in 1966. Available with either a two- or four-barrel carburetor, this block became the basis for future AMC performance engines.

In 1967, the 290 was joined by a 343 engine. In February 1968, the highly desirable 390 joined the lineup. AMC V-8 engines are unique because they are based on one basic block design. They have the same external dimensions and the 304 (used in 1970 and up), 343 (1967 through 1969), 360 (1970 and up), 390 (1968-70) and 401 (1971 and up) were obtained by boring and stroking the original 290 block. The major change between the engines was a deck height of 9.165 inches in 1966-'69 and the change in deck height to 9.208 inches in 1970. These differences affected the intake and push rod interchangeability. With some minor internal block changes, such as thicker webbing, AMC had some performance engines on its hands. Just by changing to dog leg heads in 1970, performance was increased. Unfortunately, by 1972 the compression ratio was lowered to meet emission standards and the performance capabilities of the engines dropped [[not as much as normally assumed]].

AMC reacted to its new 290 engine by coming up with some interesting parts to make AMC more competitive in the performance market. These parts have become known to AMC owners as ''Group 19'' parts. This term is used simply because of the way that AMC organized its parts books. Group 1 was engine parts, Group 2 was cooling, Group 3 was electrical, etc. Group 19 was the section devoted to high-performance equipment.

The first company to offer an AMC performance part was Edelbrock. The R4B high-rise aluminum four-barrel intake manifold (part number 448 5729 for 1967-'69 and number 448 8409 for 1970-up) took its place in AMC history. These intakes were sold through the dealers with the part number cast in them and were also offered with out the part number through Edelbrock.

The R4B high-rise aluminum four-barrel manifold has it's roots in Group 19 in AMC history. These intakes were sold through dealers with the part number cast in them and were also offered without the part number thru Edelbrock.

If the R4B wasn't good enough, Edelbrock offered a Cross Ram intake, the Edelbrock STR 11. This dual-carbed, two- piece intake was made of aluminum and had a removable top half. A few hundred were made with the AM part number 448 6228 stamped in them for 1967-'69 and 448 8411 for 1970 and up. Edelbrock also offered them without the part number stamped on them. AMC offered only the intake and linkage, so the carb selection was up to the owner, but anything over about 650 cfm didn't work particularly well. No air cleaner assembly was offered and no provisions were made for the heater hose and control, The intake also did not have an inlet for the brake booster line and didn't have enough vacuum for a power brake unit. These intakes were used on all SS/AMXS.

The Edelbrock STR11 Cross Ram intake is a dual-carbed, two-piece intake made of aluminum which featured a removable top half.

What good is a new intake without a new carb? AMC offered an optional Holley three-barrel carb with vacuum secondaries to replace the Carter AFB. The carb was used for all years and was available as part number 448 5730 or with the R4B and the carb as a set (1967/69 448 5731 and 1970/up 448 8410).

The heat passages needed some work before bolting on the intake because the exhaust gases passed under the intake. This warmed the incoming fuel and operated the automatic choke. Unfortunately, warm fuel in performance driving (i.e. drag racing) doesn't help getting to the end first. To alleviate the problem, AMC offered a special intake manifold gasket to block the passage off (1967-'69 448 8475 and 1970- up 448 8476).

The 290 and 343 had cast ''malleable'' connecting rods which were not exactly performance oriented. For these engines, AMC offered forged connecting rods (number 448 5725). The cranks were made from modular iron, so a special forged steel crankshaft (number 448 5728) was offered, A cam kit was overed that consisted of the cam, pushrods, lifters, double valve springs, seals, keepers, retainers and studs (1967-'69 with standard and four-speed transmission, number 448 6719 and 1970-'71 with standard and four-speed transmission number 448 8413). The 390 and 401 rods and cranks were forged steel from the factory, All AMC pistons were cast-aluminum. Different compression ratios were achieved by the dish on top. The factory recommended use of forged pistons for performance applications but did not include these parts in the Group 19 parts. They recommended contacting J. E., Venolia, etc., for information. A few 360 four-bolt main blocks were also available as part number 448 8937 in 1970.

The Group 19 cam kit consisted of the cam, pushrods, lifters, double valve springs, seals, keepers, retainers and studs; as wellas a forged crank and heat blocker manifold gasket.

Special performance rocker arms with longer screw-in studs were part of the Group 19 parts. The studs were number 448 7918. The set consisted of keeper nut (448 7987), hold down (448 7988) or rocker arm, keeper nut and hold down under part number 448 7331. A complete set was available as part number 448 7989.

Special performance rocker arms with longer screw-in studs were also part of the Group l9 parts.

A dual-point ignition was not on AMC'S factory list, so that problem was eliminated with the addition of a Mallory dual-point with tach drive (448 8062) or without (448 8049). The complete high-performance ignition system could be ordered as 448 7900 without the mechanical tachometer drive and as 448 7901 with mechanical drive. A special three-piece distributor cap and external condenser was pad of the package. In addition, a Capacitor Discharge Ignition System was offered under part number 448 5742.

A complete high-performance Ignition system could be ordered with or without the mechanical tachometer drive.

ln addition to the high-po ignition system, Group 19 also offered a special capacitor discharge system.

The first thing that most people do to add horsepower to their car is the addition of headers. Although AMC did not offer them directly, it told AMC owners where to buy the headers and assigned part numbers 448 5727 and 448 5726 to them. Jardine, Doug Thorley and Bellanger were the three California firms the factory recommended. AMC also offered a 8.5-quart deep sump oil pan (448 5741) which had to be ordered directly from two California companies, Aviad Metal or Racing Components.

Other special orders in the pads book were a set of heavy duty rear brake drums (448 5736 and 448 5737) or heavy duty front disc brakes with hub and caliper (448 5732 and 448 5733). Rear disc brakes with hub and caliper (448 5734 and 448 5735) were also available. All of these parts could be special ordered from Ronnie Kaplan Engineering. the company that helped build AMCs Trans Am cars. Kaplan also offered a l5x8-inch road wheel, along with American Racing Equipment.

Gears were also overed to improve the quarter-mile times. For 1967, part number 320 8551 got a 4.44:1 gear. For 1968, a 3.73 (448 5749), 3.91 (448 5750), 4.10(320 8546), 4.44(326 9854) and 5.00 (448 6587) could help move AMCS a little faster. But what good are new gears if your car just spins? To help with that problem, a positive-locking differential could be ordered as part number 448 6997.

Group 19 equipment featured a variety of gears to improve the quarter-mile performance.

Although torque links were standard items on AMXs, they were Group 19 parts on the Javelin and V8s such as the SC/Rambler (these could also be used on the Hornet and Gremlin). Special plates were bolted to the frame and part number 448 5582 was used for the Javelin and 5448 5753 for the SC/Rambler.

Although torque links were standard items on AMXs, they were Group 19 parts for the Javelin, SC/Rambler and Gremlin [[and Hornet..and therefore, Spirit and Concord]].

Group 19 also offered a couple of non-mechanical parts. A full front fiberglass spoiler was available for the 1968-'70 AMC and Javelin as part number 364 1522. The spoiler mounted by brackets to the lower fender braces and in the center by a bracket.

The rear deck lid could sport a rear wing (899 2357). The first version did not have any metal end plates attached to the spoiler. Because of problems with the original spoiler, a second version was produced. The Group 19 part and the spoiler used on the 100 Trans Am Javelins produced were made of fiberglass and had a metal end plate attached to each end of the spoiler. The spoiler rode between two metal ''stands'' that attached to the deck-lid. The Group 19 spoiler had two holes drilled in the bracket so the spoiler could ride in either location.

Group 19 also offered a couple some non-mechanical parts, like a full front fiberglass spoiler and an adjustable rear wing.

Two other spoilers were offered on AMXs and Javelins but they were not Group 19 parts. A stainless steel front spoiler (899 2553) was available on 1968-'70 AMXS and Javelins as an accessory. The Mark Donohue spoiler was used on 1970 Javelins only and was a regular part. A roof spoiler was also available on the 1969-'70 Javelin only as a regular part.

There was no great mystery about the Group 19 parts, but they have gotten very difficult to find through the years. The spoilers are available in reproduction, but the other parts are "look until you find them" items.

Group 19 parts could only be ordered from the dealer and could not be special-ordered on a car directly from the factory. Some of the parts caused minor problems, like not being able to close the hood on your car when it had an R4B and stock air cleaner, no air cleaner available with the Cross Ram and headers that hung too low. But, with the addition of these parts, at least AMC let people know that there was an alternative to Grandma's Rambler!