Forgotten Powerhouse: One Of The Rarest Production Engines From AMC’s Golden Era

The American Motors Corporation would be considered an afterthought, except not that many people remember them. They were always in last place behind the Big Three American automakers, and then were absorbed by Chrysler, never to be heard from again. AMC never had the resources to compete, and it was an extremely poorly run company, but somehow they managed to build some killer rides, especially during the Golden Age of muscle cars.

Being a smaller company, their models are rare simply because they didn't have the sales numbers of the big boys. Even in that, there were some elusive cars, with even more scarce engine options. The 1970 AMC Rebel Machine is one of the coolest classic muscle cars from any manufacturer, and its exclusive 390ci V-8 is a genuine unicorn engine. Maybe most of the collecting public has forgotten about this rare powerplant, but TopSpeed, and hopefully our readers, have nothing but love for it.

The AMC Machine 390

Unlike most other automakers, AMC didn't have small-block and big-block families of V-8s, but rather a single-block size that they used for all of their engines. It was, however, very close in size to the other manufacturers' small blocks, so that's what they are considered. One thing that differentiates the AMC engines is that they used heavy-duty parts so they could withstand high-revving conditions, whereas other big-displacement small-blocks could break connecting rods with extreme high-speed usage. AMC introduced the AMX 390ci V-8 in 1968, which produced a respectable 315 horsepower and 420 pound-feet of torque.

The Machine 390 Specs

In 1970, AMC moved from the “short-deck” second-gen V-8s to the third-generation “tall-deck” engines, which, as the name would suggest, grew in deck height. The 390 proved to be both popular and bullet-proof, so it continued into the next-gen with the same power output. AMC did create a special variant for use in their 1970 Rebel performance trim, known awesomely as “The Machine.” This Machine's 390ci V-8 pumped up the muscle to 340 horsepower and 430 pound-feet of torque, for AMC's most badass ride of the Golden Era. Sadly, both the Machine and the Machine 390 were only around for one year before discontinuation.

The Machine Difference

The Machine 390 had a special cam, heads, valvetrain, but the biggest difference from the regular 390 was the improved intakes. With a functioning hood scoop on The Machine car, the ram air-style intake did a better job of getting oxygen into the mix, which helped pull an extra 25 ponies from the 390. It also came equipped with a 690-cfm Motorcraft four-barrel carburetor, as well as a redesigned exhaust system that also contributed to the added power.

Stroked Out 401

Both the 390 and the Machine 390 were replaced in 1971 by the 401ci V-8, which was essentially the same engine that had been stroked out to achieve the additional displacement. More cubic inches, however, didn't translate into more power as the 401 was rated at 330 horsepower in 1971, and then, when detuning ended the classical muscle car the following year, it was downgraded to 255 horses. The 401 was actually still a pretty good engine that was produced until 1978, and it had its roots in the 390.

The Machine

The Machine 390ci V-8 was designed specifically to go under the hood of AMC's greatest muscle car, The Machine. The car is actually called The Machine, but it is often listed as an AMC Rebel Machine, because “AMC Rebel The Machine” just sounds weird. It started out as a collaboration between AMC and Hurst Performance, but the partnership faded away as production began. Introduced in 1970 as a performance trim of the fifth generation Rambler Rebel, shortened to simply “Rebel” in 1968, The Machine was also an appearance package with killer striping, the most famous being the red, white, and blue scheme.

1970 Machine Power And Performance

The Machine featured a hood-mounted tach, integrated into the ram-air scoop, and a Borg-Warner T-10 four-speed manual transmission with a Hurst floor shifter. It also had a heavy-duty suspension with station wagon rear springs, with a higher load rating, that gave it a raked look, which only added to its already aggressive stance. Additionally, the Machine had disc brakes, which, when combined with the improved suspension, made for the best-handling car of the classic era. Most muscle cars had float, roll, and bounce to their ride, but the Machine was tight in the corners and smooth on the straightaways.

Production

The first 1,000 Rebel Machine cars shipped were in the iconic white body with red and blue striping, but after that, it was opened up to 17 different paint schemes. There is no way of telling how many of each color were produced, but the total run for The Machine was just 2,326 units. Since the Machine 390ci V-8 was both standard and exclusive to The Machine, that makes the engine one of the rarest of the Golden Age of American Muscle and in the company of some truly legendary powerplants.

Rare Classic V-8s

• Pontiac 400 Ram Air IV - 1,808 units
• AMC Machine 390 - 2,326 units
• Chevrolet 454 LS6 - 4,475 units
• Chrysler 426 Street Hemi - 9,778 units
• Chrysler 440 Six Pack/6BBL - 13,883 units

Name Game

The Rebel Machine was a one-hit wonder, being discontinued after 1970 and taking the Machine 390ci V-8 with it. In fact, all 390 engines were replaced by the 401, and the Rebel name was retired in favor of “Matador” for some reason. There was a lot of social unrest in the early '70s, so AMC felt like the name “Rebel” was kind of negative, but whatever mindless exec made that determination is nuts, as it's the most badass nameplate in muscle car history. Also, why would anyone name a car after the guy holding the cape, when it's the charging bull that fits a muscle car's ferocity better?

AMC's 390 Lineup

The AMC 390 engine in any form was only produced from 1968-1970, so any car equipped with it is a rare find. Generally speaking, the 390 was part of an AMC top-performance trim or package, like the SST or “Go Package.” However, just because a car was an SST, didn't necessarily mean it had a 390 under the hood, and finding the exact number of vehicles produced with that engine is quite difficult. There were 127,066 Ambassador SSTs sold between 1968 and 1970, but probably only 46,048 had a 390.

AMC 390 Rides

• 1968-1970 AMC Ambassador - 46,048 units (est.)
• 1968-1970 AMC AMX - 6,725 units (est.)
• 1968-1970 AMC Javelin SST - 5,707 units (est.)
• 1968-1970 Rebel SST - 15,540 units (est.)
• 1970 AMC Rebel Machine - 2,326 units

The problem is, there aren't any reliable sources with production numbers by engine, for most AMC models. The total production of 390 cars for the Javelin is mixed up with the numbers from the AMX, so it's an educated guess with those two. It is also unclear if the Rebel numbers reflect the Rebel Machine production as well. One thing for certain is that there were 2,326 Machines built, which means there's a hard number of 2,326 Machine 390ci V-8s produced.

Rage Against The Machine

The 1970 AMC Rebel Machine and its Machine 390ci V-8 are undeniably awesome, but much like in the Golden Age, they don't get the same respect as the Big Three muscle cars in the collector's market. A Ford, GM, or Mopar muscle car with a similarly limited production run would likely be a half-million dollars and up ride, but The Machine is at best worth around $100,000 according to Hagerty and as little as $45,000 in perfect shape with J.D. Power's valuation.

1970 AMC Rebel Machine Values

• Original MSRP: $3,475
• Adjusted for Inflation: $28,256
• Classic.com auction sales: $36,000 - $145,750
• Hagerty Valuation: $36,200 - $103,000
• J.D. Power Retail: $10,950 - $45,000

A lot of posted vehicle values are theoretical, but on Classic.com there are Rebel Machines that have sold at auction recently for almost $150,000, and obviously some that went for substantially less. In the real world, a cherry, matching-numbers 1970 AMC Rebel Machine is a six-figure ride, but really feels like it should be worth so much more given its inherent coolness and rarity. The good news for collectors is that something this head-turning and mind-blowing can be picked up for a genuine bargain price.