Countless General Motors test vehicles never see the light of day. Take this one: a 1962 Chevy Impala with a flat-10 engine and front-wheel drive.
It’s said this unusual project came to pass in 1961 as Chevrolet engineering was developing an improved, second-generation version of the Corvair air-cooled six that employed integrated cylinder jugs and heads (in part to control oil leaks). In order to justify the cost of a new engine, Frank Winchell’s engineering staff studied a wider range of applications for the Corvair’s air-cooled, pancake architecture, constructing four-cylinder, eight-cylinder, and ultimately, a 10-cylinder experimental engine that displaced 300 cubic inches (above). On paper at least, the flat-10 should be reasonably smooth and good for an easy 250 hp. Reportedly, there was even a 12-cylinder version that existed in drawings.
Meanwhile, GM was also in the early stages of development in a new front-wheel drive system that would eventually appear in the 1966 Oldsmobile Toronado. So the flat-10 engine was coupled to a front-drive transaxle adapted from Corvair and Pontiac Tempest components and then turned 180 degrees so the engine was out front. This powertrain was then installed in a 1962 Chevy Impala Sport Coupe, and an extended hood and front fender assembly was constructed in fiberglass to cover the hardware. As implausible as it may seem, the front/rear weight distribution of this unusual setup was said to be acceptable.
While the long-nosed Impala was no thing of great beauty, it evidently served its purpose as a test mule for the flat-10 engine and front-drive system. But the second-generation Corvair engine family was never sent into production, so the project was concluded and as the story goes, the car was scrapped soon after.
What a find! As a Corvair enthusiast and former owner I’ve read the stories about the other configurations of the Corvair’s engine – and the full-size Chevy powered by them – but have never seen a photo. Also, I’m not sure I ever knew that the big Chevy was front-wheel-drive.
I can see at least one reason that may explain why this design was abandoned: The benefits wouldn’t justify the additional cost. Compared to a conventional straight six or V8 there are many more parts – separate heads, pushrod tubes, and multiple carburetors that were practically required (although they were an option on Chevy V8s). And every one of these additional parts creates another potential failure point, such as leaks. And that doesn’t even go into the tooling costs, or the additional cost of building the block from aluminum.
The stretched nose of that ‘62 looks like it was designed by the same team that designed the ‘60 and ‘61 Plymouths.
Yes, now that you mention it I can totally see the Plymouth resemblance.
Upon doing some additional reading, I wanted to point out an error in my original post: There would have been more parts, but not in the form of pushrod tubes, since the individual cylinder heads would have had the pushrod tubes cast into them. My apologies.
Thanks interesting
GM went through a period of emphasis on building a car with a flat floor, which eventually only Corvair and Toronado platforms had. We know now that nobody cares, as every car made has the center cockpit blocked with a huge obstruction. But they really were trying to innovate by doing cars with a flat floor.
I think you’re right. While families with four or more kids were not all that uncommon back then, I think that GM greatly overestimated the cost and compromises the buying public was willing to bear for the benefit of a flat floor. At the same time, all of Detroit’s Big 3 seemed to have taken steps throughout the 1960s to reduce the size of the dreaded transmission hump. And if you carried six adults on a regular basis, station wagons of that era could do that AND provide additional cargo room.
In addition to the Corvair and Toronado, the first-generation Pontiac Tempest also featured a flat floor, due to its rear-mounted transaxle.
With all the BEV’s being introduced, flat floors will again become common.
Yes, but as Joe Bays mentioned above, there’s a pretty good chance that a huge center console will be placed smack dab in the middle of that flat floor. But at least the front seat occupants get a center armrest (something I wouldn’t want to give up) as part of the bargain!
A complete write-up on this prototype can be found in Corsa Communique Volume 17 Number 4, from April 1995.
I miss the bench seat with the middle fold down arm rest plus the column shifter talk about some room. The new cars with the center console take up so much space . For what. Now you talk about flat floors that would be the best .Remember the last rear wheel drive Olds. Cutlas two bench seats column shifter center arm rest that was car.especially the 2dr. Out sold Honda for years the floor were not flat But for young family 2 adults 3 kids the best
When I was working on GM’s small car globalization program in the mid-late 1990s, there was much excitement about the “Power Cube” program that would have combined engine and transmission castings into one piece. The packaging efficiency gains (ie, lower hoodline, reduced front overhang) were dramatic. There was talk of line-4, -5 and -6 versions. The performance of the 6-cylinder version in a Saturn LS mule was amazing. But the casting was massive and there were doubts about its manufacturability. In addition, it was competing for capital and resources against the “Atlas” truck engines, which eventually won out. Would be great if someone has more background — there’s very little online about the Power Cube project as it never got past the mule stage. I wonder if any of the development cars were kept — fascinating piece of technology.
You’ve supplied more information about the Power Cube than any other source I’ve found online. Automotive News has an article from 1997, which includes:
About five months ago, some sources say GM nixed a proposed inline six-cylinder engine program called ‘Power Cube,’ which would have replaced the 3800 Series II V-6.
Engineers say an inline six-cylinder engine is more balanced and quieter than a V-6. It would have been offered in 3.5-liter and 3.7-liter sizes.
Bill, that AN article was the only reference I have been able to find. There was one other slightly more detailed article I ran across in the past, but I’ve not been able to find it despite various searches, so I was hoping that someone involved with the program might read this and contribute more details. One of the things I most enjoyed about working at GM was the availability of resources to work on projects that really pushed the technology envelope, even if there was a limited likelihood that many of them would reach production. As a similar example, there was a great deal of work between GM Powertrain and Design to develop a “barrel forward” transmission design that would reduce the front overhang of FWD cars. This was a less dramatic approach than Power Cube, but would still have required a major investment in GM’s massive automatic transmission production facilities, likely the major reason it was never pursued.
That impala is a very nice collectible with unusual features 👌