How Did the AMC Generation 1 Engine Come to Be?

In our History Section we detail how the engine was born out of necessity, but what we didn’t say was that AMC was very late to the OHV V8 party – so it was more than necessity – it was desperation. Nash Kelvinator was a company of dichotomies: first to offer modern, in-dash air conditioning, first to take real streamlining seriously in a quest for better mileage, first to try to meld interior roominess with modern styling – but last to see the value in a powerful V8 for their large size cars. By the time the mid-fifties rolled around, if you didn’t have an OHV V8 in your lineup, you were doomed to moribund sales. One of the major reasons for George Mason’s quest for a Packard merger was their engine and transmission technology.

When Packard informed Nash that it was going to “pull the plug” on the supply of their V8, by the end of 1956, AMC was caught without a viable alternative. Acquiring Hudson did not help as their aging 308 in-line six was reasonably powerful but heavy and at the end of its potential. Worse, there really wasn’t anyone on the powertrain engineering team with any OHV V8 knowledge, What to do?

Enter David Potter of the recently defunct Kaiser-Frazer Company. Potter was a powertrain engineer for Kaiser and had headed the team that had played with an experimental V8 of their own design; a 288 cu. in. unit primarily created Potter himself. At some point K-F decided it did not have the money to build this engine. At somewhere close to the same point in time, David Potter left Kaiser for a job at AMC, which neatly coincided with George Romey’s decision to build a new V-8. When interviewed about the K-F V8 in the 1970s, Potter was vague about whether he brought the design with him or just did something similar from scratch, but surviving pictures of the K-F 288 show an engine that appears identical to the first-generation AMC V8.

The speed of the new AMC V8’s development of less than 18 months from decision to production at a time where only testing could bear out paper design suggests that the Kaiser work was accepted as what would normally have been AMC’s preproduction process. It also suggests that AMC jumped on David Potter’s V8 quite literally as soon as they became aware of its existence.

The Mighty Mite 250

The first edition of this engine, at 250 cubic inches, appeared halfway through the 1956 model year in Nash Ambassador “Special” and Hudson Hornet “Special” models. The Specials were not only a lower trim level than the Packard-powered Ambassadors and Hornets, which remained in production but were seven inches shorter, as they used the Statesman (Rambler) chassis. To make a performance statement for their new engine, the AMC V8 went into what had been the shorter Nash Statesman/Hudson Wasp platform, which had been powered by Nash and Hudson sixes at that time.

The new V8 also used a GM Hydramatic transmission instead of the troublesome Packard Twin Ultramatic. (AMC had used Hydramatics behind its sixes, as both Nash and Hudson had done before their merger). By designing the bell housing to accept GM transmissions, AMC avoided being shoved into another tenuous supply situation as they had numerous divisions’ products to choose from – including independent Borg-Warner who made a unit that could be used by GM vehicles. (Early 1957s AMC V8s used GM Hydramatics, while a switch to Borg-Warner automatics took place somewhere in the middle of the model year).

Although the 250 V8 got a sneak preview in the Ambassador Special and Hudson Special of 1956, it was always intended as the Rambler V8. It was the smallest displacement passenger car V8 on the market in 1957, but its smaller size was not a handicap at all in the smaller Rambler, especially with its standard dual exhaust. Horsepower output in 2 barrel configuration was a more-than-respectable 190, the same rating as Ford’s entry-level 272 and higher in HP than the first two V8s on Chevy’s 1957 options list.

Next – a Bigger Bad Boy

But AMC wasn’t standing still. For a small company, they still had some chutzpah and had the larger 327 cu. in (4.0″ bore x 3.25″ stroke) waiting in the wings for the Ambassador and all of the Hudson line. The cover of the 1957 Hudson brochure announced “Power’s Up – Price’s Down”, and both claims were true. The big 1957 AMCs could be sold for less since the Company no longer had to pay Packard’s price for engines. And the 327 had 255 solid horsepower, a higher number than the previous year’s Packard V8 despite the Packard unit having 25 more cubic inches, ostensibly because Packard insisted that Hudson and Nash’s engines produce less horsepower than the virtually identical engine used in Clippers. This was accomplished by the use of thick head gaskets, which lowered the compression ratio on AMC engines, and the horsepower rating.

The big surprise took place in December of 1956 when AMC introduced the awesome Rambler “Rebel”, which combined the new 327 from the big cars with the smaller body of the Rambler four-door hardtop. Rebel 327s differed from the Ambassador/Hornet 327s by virtue of mechanical valve lifters and a higher compression ratio. (Some say a special cam was fitted, but the simple addition of a mechanical cam over the hydraulic, would effectively increase the duration as seen at the valve because there would be no cushioning of the cam ramps). The Rebel was supposed to be delivered with Bendix electronic fuel injection, but production problems in street trim precluded this. When the FI worked, the Rebel engine produced 288 HP, more than any engine in this size range!

But when the Ambassador 4-barrel carb was fitted instead of the FI, both the Rebel and the standard Ambassador engines were rated at 255 hp. it was assumed that if delivered, the FI would have been optional; it is surmised that the Rebel 4-barrel was slightly underrated, perhaps to make the stillborn 288 HP fuel-injection option appear to be more of an improvement.

It didn’t matter; in even 4-barrel trim the Rebel was a real screamer. Motor Trend magazine said the only 1957 model they tested that beat the 4-barrel Rebel’s 0-60 mph time was the Corvette with the fuel-injected 283. Even the mighty Chrysler 300C came in a tenth of a second behind the Rebel in 0-60 time. They knew that the 1957 Rebel was supposed to offer a Bendix “Electrojector” electronic fuel injection system, with its 288 horsepower, which Motor Trend believed would have proven even faster than the “fuelie” Corvette had it made it to production.

Regardless, by the end of 1957 and only 2 years after the decision to build their own V8, AMC had a modern, solid, dependable, and powerful engine that would soldier on for ten years in various forms.