Vintage R&T Road Test: 1956 Corvette, Powerglide And Stick Shift – Fast And Faster

Since we’ve been on the subject of Powerglide here lately, comparing how it performed against manuals and other automatics, here’s something on the other end of the spectrum from six cylinder sedans. As you undoubtedly know, the Corvette only came with PG in its first three years, but starting in 1956, a new close-ratio three-speed Saginaw unit was the new standard transmission—thanks to Zora Arkus Duntov—and the PG was now optional.  R&T tested two of the newly-restyled ’56s, both powered by the optional 225 hp 265 cubic inch V8.

In addition to the restyle, the ’56 with PG was also about 200 lbs heavier than the ’55 w/PG, thanks to improved amenities such as windup windows and a power top, and others. The ’56 with PG only had some 600 miles on it, so it was still “tight”. Between the extra weight and the tightness of the engine, the ’56 PG Vette was a bit slower to 60, but caught up at 80 and beat the ’55 to 100.

VinceC covered the development of the Corvette and its three and four-speed transmissions here in great detail, and this chart he made of these Corvette comparisons is from that post. The three speed manual, with its close ratios, was quicker, especially at the higher speeds. R&T didn’t publish the 0-30 times for both, but did say that the PG car “gets away quicker from a start than the stick-shift”. The manual’s 2.21:1 first gear was a bit high, best suited for racing, which was Duntov’s priority. With a broken in engine, the PG car would likely have narrowed the gap to 60 and the 1/4 mile by possibly as much as 50%.

In any case, the PG Corvette was a very brisk car for the times, when anything under 10 seconds to 60 was fast. And of course the stick shift Corvette was exceptionally quick for 1956, essentially world-class fast, as in faster than the Mercedes 300SL. And if that wasn’t fast enough, an optional Duntov cam bumped the rating up to 240 hp.

OF course only one year later, the fuel injected 283 in the ’57 Corvette and the new 4-speed B/W T-10 transmission (designed by GM) made the ’56 look suddenly slow. 0-60 now came in a breathtaking 5.7 seconds, and the 1/4 mile was blown away in 14.3 seconds. Admittedly, the ’57 did have steep 4.11;1 rear axle gears. It would be some years before another Corvette would be as quick, due to weight gain, as well as any other production car in the world.

The twin four-barrel induction system showed signs of a bit of bogging at take-off. That’s a lot of venturi area for a 4.2 L V8, but the Chevy’s excellent breathing heads were able to take full advantage of them once under way. And it ran cleanly and smoothly to 6000 rpm.

Handling and cornering abilities were deemed “good to excellent”.  There was a bit of cowl shake over 100 mph.


Related CC reading:
Automotive History: From Powerglide to 4-speed – The History of Transmissions on Early Corvettes

Vintage R&T Road Test & Tech Report: 1954 Chevrolet Corvette – “Is It Really A Sports Car?”

Automotive History: 1957 Chevrolet Fuel-Injected 283 V8 – Ahead Of Its Time And The Competition