1973 Chevrolet Corvette LT-1 Coupe

Detail changes for 1973 produce mixed results.

By R&T staff January 21, 2003

Traditional virtues have a way of fading into the background. In every field there is a constant flow of new and exciting things, ideas, techniques, attracting our interest and diverting our attention. We tend to think in terms of the new way, the fashionable way, and not to wonder if the new way is really the better way.

The has been with us now for 20 years. In 1973 as in 1953, it’s a true sports car. These days it’s a little softer and a little more raw than most sports cars at the same time. The Corvette has always been bigger than it needs to be, and this year it has grown externally once again with no gain in useful inside space or access. There is no more racing, not even under the various guises of the past. The ultra-performance engines are gone. Most important, the ’73 Corvette is not the exciting new Corvette, not the mid-engine car promised to us (and by us to you) for this year. That is still most definitely on the way, however. We don’t pretend to understand the corporate policies and politics involved in its delay, but right now while other manufacturers of fast sports cars turn more and more to the mid-engine layout, we can say in good faith that the present Corvette — the front-engine, rear-drive, fiberglass-body-car — will be with us for three more years at least.

But don’t despair. The 1973 hasn’t grown much from the 1972. Its nose has been extended to accommodate a deformable covering for a sturdier bumper that gets displaced rearward in a 5-mph impact with a barrier, but that adds only 2.2 in. to total length — not much for a bumper these days. The test Corvette was only 35 lb heavier than a comparable 1970 model with the same equipment (air conditioning, power-assisted steering, etc). It’s big and heavy, yes but not much bigger and heavier than before.

The major change this year was in the tires. For several years Corvettes came with Corvette-only tires, built to specifications drawn up by Corvette engineers. They were of conventional bias construction at first, then bias-belted when the other sports cars had changed over to radials.

This year the Corvette finally has radial tires, from either Goodyear or Firestone. Our test car had the Firestones. The change was not altogether desired by the Corvette people, but tiremakers showed a lack of interest in continuing to build a specialized tire for the Corvette and there was no problem getting steel-belt radials of the right size. So it was done, with some gains and some losses. Cornering power has been reduced, braking distances have increased and the tire used now is rated for a lower cruising speed, down from 140 to 120 mph. This last is academic for all but a handful of buyers, of course, but bad for the image. Tire life will be better, the car is more stable at speed, and wet-weather grip is improved. One could wish that the radials used were the best grade, like the Michelin XWX, but Zora Arkus-Duntov says such high-speed radials are noisy (true) and much more expensive (also true).

The buyer is assumed willing to pay for fancy wheels, though, and a new option this year is a set of American Racing Equipment alloy wheels in 15 x 8 size. They are attractive and do reduce unsprung weight, but their chief attraction is that they reduce total weight, by 8 lb per wheel and 40 lb per set. The 1973 car has guard beams in the doors and added insulation all over, along with the heavier bumpers, so to be strictly accurate the car has gained 75 lbs and these wheels allow it to lose 40.

There are three choices of engine this year; the standard 190-bhp 350 V-8, the giant 454 V-8 with 275 bhp and more weight, and the high-performance 350 with somewhat higher compression ratio, different camshaft and 250 bhp. Our test car had the latter engine, mated to the close-ratio 4-speed manual transmission and the highest numerical final-drive ratio in the catalog, all the better for maximum acceleration.

This engine and transmission work well together. As the measured data show, the L82 (that’s the option number for the engine) makes the Corvette competitively quick — not so quick as the former race-based versions but more than quick enough to be up with other high-priced sports and GT cars. This engine can be bought with air conditioning, which the old racy engines could not have, so the buyer benefits here as well. And this 1973 engine does well in terms of drivability. No stumbles, no surge, thanks largely to the use of an air pump to control emissions instead of relying entirely on lean carburetion and retarded ignition.

Corvette LT-1 Coupe
PRICE
List price, FOB Detroit	$5635
Price as tested:	west coast $7513
Price as tested includes standard equipment (4-wheel disc brakes), 350 L82 eng ($299), air cond ($452), AM/FM stereo ($276), alloy wheels ($175), power strg ($113) & brakes ($46)
IMPORTER
Chevrolet Division General Motors Corp. Detroit, Mich. 48202
GENERAL
Curb weight, lb	3520
Test weight	3815
Weight distribution (with driver), front/rear, %	51/49
Wheelbase, in	98.0
Track, front/rear	58.7/59.5
Length	184.7
Width	69.0
Height	47.7
Ground clearance	4.3
Overhang, front/rear	42.8/43.9
Usable trunk space, cu ft	4.4
Fuel capacity, U.S. gal	18.0
ENGINE
Type	ohv V-8
Bore x stroke, mm	101.6 x 88.4
Equivalent in	4.00 x 3.48
Displacement, cc/cu in	5737/350
Compression ratio	9.0:1
Bhp @ rpm, net	250 @ 5200
Equivalent mph	115
Torque @ rpm, lb-ft	285 @ 4000
Equivalent mph	89
Carburetion	one Rochester (4V)
Fuel requirement	regular, 91-oct
Emissions, gram/mile:
Hydrocarbons	2.7
Carbon Monoxide	20.0
Nitrogen Oxides	2.4
DRIVE TRAIN
Transmission	4-sp manual
Gear ratios:
4th (1.00)	3.70:1
3rd (1.27)	4.70:1
2nd (1.64)	6.07:1
1st (2.20)	8.14:1
Final drive ratio	3.70:1
CHASSIS & BODY
Layout	front engine/rear drive
Body/frame	steel ladder frame, separate fiberglass body
Brake system	11.75-in vented disc front & rear, vacuum assisted
Swept area, sq in	639
Wheels	cast alloy, 15 x 8
Tires	Firestone GR 70-15
Steering type	recirc ball, power assist
Overall ratio	17.6:1
Turns, lock-to-lock	2.9
Turning circle, ft	37.0
Front suspension:	unequal-length A-arms, coil springs, tube shocks, anti-roll bar
Rear suspension:	lower lateral arms, axle shafts as upper lateral arms, transverse leaf spring, tube shocks
INSTRUMENTATION
Instruments: 160-mph speedo, 7000-rpm tach, 99,999 odometer, 999.9 trip odo, oil pressure, coolant temp, ammeter, fuel level, clock
Warning lights: brake system, door ajar, headlights, seatbelt, high beam, directionals
ACCOMMODATION
Seating capacity, persons	2
Seat width	18.0
Head room	35.5
Seat back adjustment, deg	0
MAINTENANCE
Service intervals, mi:
Oil change	6000
Filter change	12,000
Chassis lube	6000
Tuneup	12,000
Warranty, mo/mi	12/12,000
CALCULATED DATA
Lb/bhp (test weight)	15.2
Mph/1000 rpm (4th gear)	22.0
Engine revs/mi (60 mph)	2725
Piston travel, ft/mi	1580
R&T steering index	1.07
Brake swept area, sq in/ton	336
RELIABILITY
From R&T Owner Surveys the average number of trouble areas for all models surveyed is 12. As owners of earlier-model Corvettes reported 12 trouble areas, we expect the reliability of the Corvette to be average.

 

From R&T Owner Surveys the average number of trouble areas for all models surveyed is 12. As owners of earlier-model Corvettes reported 12 trouble areas, we expect the reliability of the Corvette to be average.

The close gearing is entirely suitable for this engine, with an overall ratio in 1st low enough to make comfortable starts from rest and intermediate ratios that keep the engine close to peak power during acceleration. There’s a choice here, because the engine has a wide range of torque and will pull strongly from 1500 to 5600 rpm. You can leap from 1st to 4th, zoom around town in 2nd or 3rd, putter along in 4th at low speed, or whatever you wish. And the gearshift is uniquely light for the size of the gears it shifts. So are all the controls light, adding up to a car that easy to drive quickly and smoothly.

But not quietly; the Corvette’s noise level is still that of a sports car, to be sure. The 1973 test car was compared against a borrowed 1971 LT-1 Corvette, last of the mechanical-lifter engines and the line equivalent of the current L82. The newer car was actually louder at idle, booming 73 dBA compared to 60, and the 1973 peaked at a thunderous 100 dBA in 1st gear because of strong induction and exhaust noise. Impressive, you understand, but still loud — the 1971 car peaked at (only?) 94 dBA! At steady speeds, however, when noise level is more critical, the new car was quieter: 74 vs 76 dBA at 30 mph, 73 vs 78 at 50 and 78 vs 81 at 70. Is this a net gain? Perhaps, but Chevrolet’s objection to noisier tires seems hollow in view of the engine noise.

The radial tires are intimately involved with the new car’s ride and handling, and our skidpad figures show that its absolute cornering power has been reduced to just above average. Zora Arkus-Duntov confirms this and adds — with some regret — that on his skidpad it has dropped from 0.85g to just about what our own tests showed. The car went around the circle without much body roll and certainly without drama, mildly understeering all the way, but not very fast. This isn’t to say that the car isn’t satisfying to drive on a winding road, however, and Duntov says his wet-pavement tests showed marked improvement. Our wet-weather driving indicated this too. And the steering is more responsive. The suspension has been tuned to the tires and the ride is now less harsh — not enough suspension travel yet, but the effect is better than ever before.

Braking distances are also adversely affected; they have increased from average to not-quite-average. This is not good for a car with so much speed.

The Corvette interior has been changed very little. Some of the holdovers are poor — the location of the wiper-washer switch, for instance, the limited access to the limited luggage space and the typically clumsy GM buckle for the separate lap and shoulder belts. The fiber-optics light monitors are gone (not much loss) and it was nice, looking out across the hood, to realize that the silly hatch cover for the wipers is gone.

Generally, the drive is well accommodated. Most of the controls and switches are within easy reach, there are enough instruments and the tidy little vinyl-rim steering wheel doesn’t block view of them. Still no adjustment for the seatback, but there’s plenty of legroom and with the optional adjustable steering column the wheel can be moved up and down and back and forth. Having only two seats sllows the shoulder strap (which is on an inertia reel) to be threaded through a slot in the seatback, just above the shoulder — a nice arrangement. In all, the Corvette is a reasonably comfortable place to sit for hours.

For all its age, size and compromises, if the Corvette is equipped with the right options it is a pleasant and rewarding car to drive, and this 1973 example was one of the best Corvettes we’ve ever driven.