One version was a terror, however, but it wasn't marketed by Chevrolet. It was called the Corv8, or more commonly the Crown Corvair. It was developed by Ted Trevor's Crown  Manufacturing Co., Inc., of Newport Beach, California. The guys who dreamed up this one really had some severe brain damage. You can see them sitting there, looking at a Corvair, and saying "Hey, wouldn't it be neat if we could figure out a way to stuff a 327 into the back seat of that thing?" Yeah, it would be neat. And fast. Really, really fast.

Engine swaps were one thing in the 60s, but this was a step beyond. As difficult as this might seem, two things made it possible: The Corvair engine rotated in the opposite direction from most other engines, so that if a V8 was placed in the rear seat area (the added weight of a V8 in the original location of the Corvair engine would be abominable to drive) and coupled to the front of the transmission via a supplied custom made clutch gear and input shaft,  the car would drive in the proper direction with four speeds forward and one reverse. The switch in 1966  standard Chevrolet Saginaw gear sets in the manual transmission made it possible to  handle the torque of a V8. 

A radiator replaced the  trunk in the front of the vehicle. The engine compartment in the rear was now available as luggage space. Great! Would a Cat Scan machine fit back there? A complete kit cost  $600. The resulting guided missile on wheels weighed only 2,750 lbs, compared to 3,700 lbs for a small block Corvette, and possessed independent rear suspension of almost the same design. 

Only the '65 - '69 Corvairs are suitable for the conversion as the earlier ones have a swing axle suspension that isn't equal to the strain imposed by the bigger engine. They can be converted to the later suspension through a lot of cutting and welding, but it's  easier and cheaper to start with the proper model.

Crown's prototype with a 350 hp Corvette engine recorded an elapsed time of 12.22 @ 105 miles per hour  in the quarter mile. An advantage of this modification was that the mid engine design provided optimal handling characteristics as well as excellent drag strip traction. 

Although a few Corvairs have been modified to accept the Chevrolet big block engine, the added size of the engine makes the work significantly more difficult and the result, although a spectacular  performer, tends to be unreliable due to the added strain on the chassis and transaxles. Rides to the nervous hospital aren't always readily available, either.

Some parts are still available from jobbers, like Clark's Corvair. Another company, Kelmark, a kit car builder, offered a similar kit. Named for  Keller and Markham, the two engineers who invented the setup, The kit differed from the Crown Corv8 method.  The Kelmark system mounted the engine 11 inches further back in the car than the Crown conversion. This enabled the retention of the stock front seats, but required the turning of the transaxle 180 degrees flat to the rear end and connecting it to the engine with a bell housing adapter. A stock, long clutch shaft was used, and it turned out to be a major drawback because the shaft tended to break under the torque of a V8. A stronger replacement unit was offered by Kelmark,  solving the problem.

Kelmark offered more legroom than the Crown Corv-8, but Crown's advantage was near perfect engine placement in terms of weight distribution. Crown got closer (40/60) to the 50/50 ideal. Kelmark began building kit cars in 1969 and continued through the mid 1990s.

That ain't all folks, this seemed to be the thing to do. Mid Engineering was formed by a select group of automotive engineers and builders who designed a number of kits to convert various vehicles to a mid engine configuration. They designed a kit to install an Oldsmobile Toronado or Cadillac  front wheel drive train and engine into a late model Corvair.  I can't even imagine what this thing would be like with a hot version of the 442 engine.

There is a Yenko Stinger around that was converted to a V8. It is Stinger number 99, and Yenko did not perform the conversion. It seems that even today, people make these conversions. Next time a rather loud Corvair with no back seat pulls up to you at a stop light, keep your wallet in your pocket. Ya never know, dude.