Friday, April 8, 2011
Car of the Day:April 8, 2011
The Yatming '57 Chevy Corvette is the car for today
The 1957 Corvette included a larger V-8 and, as a mid-year addition to the options list, a four-speed manual gearbox that had long been demanded by enthusiasts. The Corvette's appearance didn't change -- not that it needed to -- except that the bodyside "coves" could now be finished in a contrasting color as a $19.40 option.
The 283-cid V-8 has become one of Chevy's most revered engines -- the definitive small-block enshrined by a generation of car enthusiasts and all the collectors who followed. It was essentially the existing 265 engine that had been bored out 1/8-inch (to 3.875 in.; stroke remained a short 3.00 in.). In Chevrolet passenger cars, the 283 delivered 185 bhp in base form, but the standard Corvette version with a four-barrel carburetor developed 220 bhp at 4800 rpm. Dual four-barrels took it to 245 and 270 bhp, and GM's newly developed "Ramjet" fuel injection system yielded 250 or 283 bhp. The last was the magic "one-horsepower-per-cubic-inch" threshold, and Chevy ads blared the news. (It wasn't a first, though; Chrysler had actually exceeded that goal the previous year with its 355-bhp 354-cid hemi V-8 in the 300B.)
Fuel injection was a foreign concept -- literally -- to Detroit automakers in the 1950s. Chevrolet turned to the technology as a way of gleaning added performance out of its two-year-old V-8 while its competitors were preparing all-new eight-cylinder powerplants of their own. The engineers borrowed a page from the European automakers' performance books and settled on obtaining more horsepower via a more precise fuel metering system than a carburetor allowed, namely fuel injection. Model year 1957 was closing fast, so a development team was formed -- and hustled.
In a relatively short period of time, the engineers put together a fuel injection system that appeared to be relatively inexpensive to manufacture and promised significant power gains. Yet initial dyno-testing showed the "fuelie" to be no more powerful than a standard dual-carburetor V-8. So it was back to the lab for more research.
Ultimately Chevrolet and GM's Rochester carburetor division came up with a workable system that not only increased top-end output but spread power over a wider rpm range. Reliability problems surfaced quickly, which together with the option's high price tag -- $500 -- rendered fuel injection a scarce commodity. Installations ran to only 240 in a total '57 production run of 6,339 Corvettes. Ramjet fuel injection was subsequently dropped from Chevy's other passenger car lines after 1958, though it remained as a Corvette option through 1965.
Despite its problems, fuel injection provided the necessary performance ability. "Fantastico!" began one ad that pictured a Corvette being unloaded from a freighter, a half-covered Ferrari just visible in the background. "Even in Turin, no one has fuel injection!" Ironically in view of the hubbub about "1 h.p. per cu. in.," the top fuelie actually delivered closer to 290 bhp -- more than the advertised 283. This was attained on 10.5:1 compression, shared with the dual-carb 270-bhp engine. The milder 250-bhp fuelie ran a lighter 9.5:1 squeeze, same as that of the 245-bhp twin-carb unit. Some historians think that in its zeal to promote Ramjet, Chevrolet deliberately underrated power on the dual-carb engines.
The 283-cid/283-bhp motor was sold as a $484.20 option; it carried the EL order code and should not be confused with the EN racing version, which, at $726.30, was sold as a package complete with column-mounted tachometer and a cold-air induction system. Chevy warned potential buyers that the EN option was not for the street and actually refused to include heaters on cars equipped with the racing package.
In the long run, the four-speed manual gearbox option was probably more significant than fuel injection for the Corvette's overall performance aura. Priced at only $188.30, Regular Production Option (RPO) 685 was essentially the existing three-speed Borg-Warner transmission with the reverse gear moved into the tailshaft housing to make room for a fourth forward speed. Ratios were again closely spaced: 2.20:1 (1st), 1.66 (2nd), 1.31 (3rd), and 1.00 (4th). "Positraction," Chevy's new limited-slip differential, was a separate option available with four different final-drive ratios to help get the most out of the new engines and gearbox in each particular driving or competition situation.
For the 1957 Corvette -- answering the previous generations' complaints about handling and braking deficiencies -- Chevrolet also issued RPO 684. This was a $780.10 "heavy-duty racing suspension" package comprising heavy-duty springs, a thicker front anti-sway bar, Positraction, larger-piston shock absorbers with firmer valveing, a faster steering ratio that reduced turns lock-to-lock from 3.7 to 2.9, and ceramic-metallic brake linings with finned ventilated drums. Add the 283-bhp fuelie V-8, and you had a car that was ready to go racing right off the showroom floor.
In almost any form, the '57 Corvette delivered certifiably staggering performance. Motor Trend clocked a 250-bhp fuelie at just 7.2 seconds in the 0-60-mph sprint. The 283-bhp version was even more formidable, with Road & Track running the same test in a four-speed with the short 4.11:1 final drive in just 5.7 seconds; it breezed through the quarter-mile in 14.3 seconds at better than 90 mph and sailed on to a maximum of 132 mph. Motor Trend took a version with the 283-bhp engine, dual exhausts, special cam, and solid lifters all the way up to 134 mph.
Check out http://auto.howstuffworks.com/1957-corvette.htm to learn more on the '57 Vette.
There are two versions of this casting. One version offers the headlights and grill casted while the version shown offered plastic lights and grill. Purchased this all metal Yat from a member on another board. Working suspension, opening doors and a metal base, yeah it rocks!