Curbside Classic: 1968 Chevmobile Impala

Paul Niedermeyer
by Paul Niedermeyer

Hybrids are big in Eugene, but some are just plain huge. The Prius is the official new car here, having dethroned Subaru. But here’s a hybrid of a different color: instead of a marriage of two drive systems, it’s a cross between two brands, the engine of one transplanted into another. Back in the day, when these were popular, the goal was speed, not better mileage. And the resulting names of these cross-species hybrids were more colorful than Prius or Insight: Fordillac, Studillac, Fordick, Fordolet. Well, here’s a new one: a Chevmobile.

Lift up this Impala’s half-acre slab of hood, and where you might expect to encounter the ubiquitous small block, or perhaps a rat motor, sits an Olds 455. There’s nothing to give that surprise away, from the outside, so fortunately its owner came out to show off his beastly mongrel. Wait a minute; looking at the pictures now, I see that the badge next to the front side-marker light that normally announces the engine size to the inquiring world is missing. Did he take it off purposely, to arouse suspicion, or to not mislead the unwary; or did this car start life as a fairly rare six-cylinder Impala hardtop coupe, one of a few thousand built that year?

Lost in surprise and admiration of that clean Olds big-block, I forgot to ask him what exactly inspired this cross-divisional heart transplant. It’s not like big-block Chevys are hard to come by. Whatever; I love it. And it’s so utterly antithetical; Chevy engines have been the overwhelming choice of engine transplants into other makes since the first small block coughed to life in 1955.

This car brings back a flood of memories wasting hours at the drug store poring over various hot rod magazines in the sixties. Engine transplants are as old as the Model T, and kids are still dropping Integra VVT engines into Civics; but I’d say the golden age was the fifties and sixties. By that, I mean the randomness of the transplants. By the seventies, the Chevy V8 was such a dominant and universal tranplantee, it got rather predictable and boring. But previously, anything went anywhere, as long as the new engine made more power, and a stout oak tree, a chain, and a come-along were handy.

There are two main eras to indulge our engine-swapping nostalgia with: pre and post OHV V8. Just to clarify, we’re talking about cross-brand swapping; dropping Ford’s flathead V8 into old Ford rails is a different category; let’s call that “updating”: expedient and cheap, but not as original or creative. In the pre-OHV V8 era, I’m thinking particularly of the Chevy and GMC sixes, and the Buick straight eight.

The Ford V8 is a legend, and we’ll find one to honor here, but the flathead design had serious intrinsic faults. That drove quite a few to plumb the performance possibilities of the OHV GM units. Contrary to the myth of the Ford being the ubiquitous hot rod engine in the forties and fifties, there was a strong Chevy stove-bolt and Jimmy contingent. A full range of after-market speed parts were available, and with their intrinsically superior breathing and thermodynamics, they put in a strong showing at the drags and Bonneville.

The big Jimmy sixes, with 270 and 302 cubic inches, were brutes, and with modified cylinder heads and five carbs like this example, they flew, as in right past a flathead Ford. And the big, long Buick straight eight had a powerful presence too, both visual and aural. Check out this one with four SU carbs! That’s from the days when not every rail had a blown Chrysler hemi in it. The rat rod scene is doing its part to revive the use of oddball engines; old sixes and straight eights are in demand again.

When the Caddy V8 appeared in 1949, it might as well have been the second coming. Two visionaries, Bill Frick and Phil Walters, quickly made a business case out of it by dropping brand-new 331 Caddy engines into the light Ford sedans for a thousand bucks. The resulting hybrid was dubbed Fordillac, and made quite a sensation. “Uncle Tom” McCahill loved it, and it caught the eye of Briggs Cunningham.

Cunningham would have taken one to race at LeMans, but the rules wouldn’t allow it. But he did hire Frick and Walters to run his Caddy racing program, which we covered in our story of the hot-rod ’50 Caddy. And when the super-low ’53 Studebaker Starlight coupe appeared, Frick and Walters were on it in a flash, creating the legendary Studillac. Here is a review by McCahill of this 125 mph coupe that could outrun pretty much anything on both sides of the Atlantic at the time.

Lest I get accused again of slighting the Olds Rocket V8, it too was popular from its arrival six months after the Caddy. But obviously, plucking new engines from the assembly line was not cheap. But as soon as they started showing up in junkyards, shade-tree transplantists were all over them. And until the Chevy V8 started filtering down, big Caddy, Olds, nail-head Buicks, and Chrysler hemis were the implants of choice.

All this distraction about hybrids, and I haven’t even started on the ’68 Impala itself. I’ve got a ’70 Impala story planned for down the road that will stay focused on the car itself, I promise. The ’68 marked the end of the fastback, and the beginning of the post-283 era. The standard V8 was now the 307, for one year only. Of course, during this golden era, just about every engine in Chevy’s vast arsenal was optional, right up to the 425hp 427 (7 liter) big block. The sleeper of the bunch was a 3500lb Biscayne two-door, with the hot 425/427.

But then this Chevmobile’s motor looks pretty warm too: Edelbrock intake supporting a big four-barrel, tube headers, probably a hot cam. And it makes nice music, when I hear it from time to time on the streets near the campus, mixing it up with all the other silent hybrids.

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Paul Niedermeyer
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  • Rpol35 Rpol35 on Nov 06, 2009

    A couple of points: 1968 was the last year for the fastback full-size Chevy and the first year that the Impala got the Caprice's formal roofline. It was an optional model called "Impala Custom". The 1969 Impala continued with the formal "Custom" but also had a semi-fastback that replaced the full fast back from '68. It was also continued into 1970. The Olds engine is a very durable engine because the block contained a high nickel content, much more so than a Chevy. Nevertheless, a Chevy rat motor, which weighs about 700 lbs. with iron heads, is going to make a lot more horsepower, primarily as a result of its staggered valve cylinder head design. The 1968 Olds 455 (new that year) had horsepower in the 370 range and perhaps 380 with the W-30 option for the 442 model. The base Chevrolet 427 (L36) in 1968 was 385 horsepower while the special order L72 was 425 horsepower. About 500 full-size '68 Chevies received the L72. I've only seen one with my own eyes and it was a matching number Biscayne. I'm not sure why the Olds had the sound that it did as mculbert references but they did sound substantial in stock form. Olds preferred a more "modular" design where bore and stroke closely approximate one another; Chevrolet always pushed for a more oversquare design where the bore is somewhat larger than the stroke. I doubt that had anything to do with the sound. It was probably related more to compression chamber design and exhaust system design; again no similarity between an Olds 425-455 and a Chevy 396-427-454.

  • Lug Nuts Lug Nuts on Nov 07, 2009

    Up until a few years ago, I owned a 65 Impala SS show car. Great to look at, but ride and handling were horrid (literally the living room on wheels as mentioned above). Rebuilding the entire suspension from scratch with modern upgrades made little difference. There's not much you can do to improve handling on a gigantic car weighing almost two tons. I finally saw the light, sold it, and bought a certain unibodied pony car of the same vintage. Zero regrets and finally respectable handling.

  • Lorenzo The unspoken killer is that batteries can't be repaired after a fender-bender and the cars are totaled by insurance companies. Very quickly, insurance premiums will be bigger than the the monthly payment, killing all sales. People will be snapping up all the clunkers Tim Healey can find.
  • Lorenzo Massachusetts - with the start/finish line at the tip of Cape Cod.
  • RHD Welcome to TTAH/K, also known as TTAUC (The truth about used cars). There is a hell of a lot of interesting auto news that does not make it to this website.
  • Jkross22 EV makers are hosed. How much bigger is the EV market right now than it already is? Tesla is holding all the cards... existing customer base, no dealers to contend with, largest EV fleet and the only one with a reliable (although more crowded) charging network when you're on the road. They're also the most agile with pricing. I have no idea what BMW, Audi, H/K and Merc are thinking and their sales reflect that. Tesla isn't for me, but I see the appeal. They are the EV for people who really just want a Tesla, which is most EV customers. Rivian and Polestar and Lucid are all in trouble. They'll likely have to be acquired to survive. They probably know it too.
  • Lorenzo The Renaissance Center was spearheaded by Henry Ford II to revitalize the Detroit waterfront. The round towers were a huge mistake, with inefficient floorplans. The space is largely unusable, and rental agents were having trouble renting it out.GM didn't know that, or do research, when they bought it. They just wanted to steal thunder from Ford by making it their new headquarters. Since they now own it, GM will need to tear down the "silver silos" as un-rentable, and take a financial bath.Somewhere, the ghost of Alfred P. Sloan is weeping.