Buyer’s guide: Chevrolet Corvette C4

By Malcolm McKay

| 5 Feb 2021

Classic & Sports Car – Buyer’s guide: Chevrolet Corvette C4

Why you’d want a Chevrolet Corvette C4

General Motors took to heart the flak about American cars not handling properly, and launched the 1983 Corvette C4 into Europe with the confident claim that it could out-corner any European sports car, generating 0.95g in corners where the likes of the Porsche 928 couldn’t hit 0.9g.

Uni-directional tyres and wheels specially developed with Goodyear helped, and there was rack-and-pinion steering, aluminium double-wishbone front and multi-link rear suspension, both sprung by unusual glassfibre transverse leaf springs and both with anti-roll bars.

Vented discs all round completed the package, which was stiffened even more for the European market.

Combined with clean looks, light weight and good aerodynamics, the Corvette promised much.

Just 205bhp from the lazy overhead-valve V8 looked a disappointment, but it had a wide spread of power and a well-tuned four-speed auto ’box: Europe’s testers were impressed, if somewhat dumbfounded by the poor ride on uneven roads.

Given a smooth surface the Corvette was unbeatable, but it seems GM had given the testers a bit too much of their own medicine, at least on Euro-spec cars; even the US version was softened for the ’88 model year.

The hatchback C4’s roof was an oddity, being removable but a pain to do so because it was securely bolted in to aid structural rigidity. This led to the return of the convertible in 1985.

The C4 also pioneered the introduction of a lot of electronics, including a digital dash that can be costly to rectify when it fails, and electronic ignition and fuel injection that give reasonable economy in everyday driving.

After buying Lotus in 1986, GM tasked the Brits with developing a hot ’Vette. The answer was the ZR-1 with an all-aluminium V8 engine, featuring four overhead camshafts and 32 valves, giving 375bhp.

The engine’s complexity plus the wider rear body, bigger brakes, wheels and tyres meant the ZR-1 was heavier than the standard C4 – but it did 0-60mph in 4.9 secs, topped 180mph, and raised the world 24-hour Land Speed Record to 175mph in 1990.

The standard C4’s performance improved dramatically during production: to 230bhp, then 240, then 245, 300 with the LT1 V8 in 1991 and 330 with the LT4.

No wonder late cars are worth more, though early ones are still fun and, unlike most ’80s cars, the steel substructure rarely rots.

Images: James Mann

Chevrolet Corvette C4: what to look for

Trouble spots

See above for some essential checks.

Under the bonnet

The LT1 engine brought serious performance to the standard Corvette, without the occasional frailties of the all-aluminium four-cam ZR-1 or the twin-turbo Callaway-tuned versions.

Check all units for signs of neglect and water/oil leaks (or mixing); any problems are more likely to be electronic than mechanical.

Ensure the radiator isn’t leaking, or clogged with leaves, and that the fans work. Overheating from a blocked radiator can cause head-gasket failure.

Electrics and body

Check all electrics work: flip-over headlights can fail, but it’s usually a replaceable plastic gear.

Check the glassfibre body for cracks and crazing.

Dashboard

Pre-1990 cars are more prone to dashboard issues than this late one.

The LCD dash was innovative but fails with age, costing c£450 to refurbish.

Wheels and tyres

Listen for clicking from worn universal joints and grumbling wheel bearings.

A limited-slip diff was standard; check tyre age as well as condition.

Chevrolet Corvette C4: before you buy

Even the earliest C4s had lively performance – though the later examples make them feel tame.

The very hard ride on early cars (especially the Euro-spec Z51 pack) was unsettling on rough roads; it was gradually softened and the advanced alloy and composite suspension components have proved durable in service.

On the L98, check for oil leaks from the front and rear crank seals (£300-plus to sort). With the LT1, inlet-manifold leaks cause poor running and the Opti-spark distributor (used up to 1994) suffers if the water pump above it weeps and the moisture corrodes the electrics – budget £1000-plus to replace both.

ZR-1s can be troublesome if neglected, but are great when working well and they thrive on use. A high tickover indicates a vacuum leak under the plenum chamber.

Upgrades are popular; the best for the L98 is a dual exhaust, and on pre-’92s losing the cats gives 20bhp+ more and takes heat away from the engine. On LT1s, cat-back systems are best.

Most cars have auto transmissions. Check the fluid is red: if it’s black or smells burnt, budget £7-900 for a rebuild.

The manual ‘4+3’ (with overdrive on 2/3/4) is robust; ensure overdrive cuts in both automatically and on the gearlever switch. The six-speed ZF is also strong, but beware of clattering from its dual-mass flywheel.

Electrics are the most likely problem area, and Japanese imports can suffer major issues due to being overloaded with extras. Diagnostics are OBD I up to 1995, then OBD II. If buying from the US, get a CARFAX vehicle history report.

Chevrolet Corvette C4 price guide*

Coupe

Project: £2000
Average: £4000
Show: £10,000

Convertible

Project: £2,500
Average: £7,000
Show: £15,000

ZR-1, Callaway, GS

Project: £8000
Average: £15,000
Show: £40,000

^{*Early cars 25% less, late cars 25% more; prices correct at date of original publication}

Chevrolet Corvette C4 history

1983 Jan Build begins (MY84**): 205bhp L83

MY85 230bhp L98, tuned port injection

MY86 Convertible added; Pass Key security

MY87 Roller tappets, 240bhp; B2K Callaway Twin-Turbo option (c500 converted to 1991)

MY88 Softened suspension

MY89 ZF six-speed manual replaces ‘4+3’

1989 Mar ZR-1 added, with 375bhp LT5V8

MY90 245bhp; driver’s airbag standard

MY91 Facelift: restyled exterior and interior

MY92 300bhp LT1; traction control standard

MY93 Keyless entry; ZR-1 up to 405bhp

MY95 Minor restyle; ZR-1 dropped

MY96 Grand Sport (GS): 330bhp LT4 engine, blue/white stripes, special trim (1000 built)

1996 Jun Last C4 produced

^{**US model year commences in October of the previous year}

The owner’s view

Serial Corvette fan Mick Howes got the bug after seeing a C3 drive past when on an army exchange tour in El Paso, Texas, and bought one on leaving the forces in 1998, clocking up 150k miles in 15 years.

He replaced it with a 1992 C4, but sold that when expensive computer issues loomed, replacing it with this 1995 coupe. His only car, it has covered 17,000 miles in three years.

“I couldn’t believe how much better the C4 is than the C3,” he says. “My first C4 was lots of trouble, but I’ve fallen in love with this one. It lives outside but it won’t rust.

“It’s so sleek, there’s something special about it – it has the family line. The clamshell bonnet makes it so easy to get to everything and I love the yellow, which is the Corvette racing team’s colour. It’s also incredibly economical: I get 20mpg locally, but have seen 34mpg on long runs.”

Also consider

The Porsche 911 Carrera 3.2/964 (left) and TVR 350i-450SE are alternative buys

PORSCHE 911 CARRERA 3.2/964

Powerful flat-six in coupé, targa and cabrio bodies. Rewarding to drive, but prone to rust despite galvanising, and oil leaks that lead to an engine rebuild.

Sold 1983-’93 • No. built c77,000 • Price now £25-80,000***

TVR 350i-450SE

Loud, dramatic and with a glassfibre body on a (rust-prone) steel chassis, the ‘wedge’ TVRs are not for the shy and retiring. Big fun, but a bad one is a money pit.

Sold 1983-’91 • No. built 2618 (including V6s) • Price now £4-25,000***

^{***Prices correct at date of original publication}

Chevrolet Corvette C4: the Classic & Sports Car verdict

The C4 Corvette is a classic sleeper that can offer close to supercar performance for far, far less than traditional supercar prices – and can be a durable, reliable and inexpensive car to run as well.

That’s if you buy a good one, of course – neglected Corvettes can still suffer from some costly issues, while rare and desirable models are already becoming a lot more expensive to buy than run-of-the-mill examples.

FOR

Late is best for performance and reliability, but all C4s offer a lot for the money
Parts are generally inexpensive
Good club back-up
Surprising economy make these great all-rounders

AGAINST

Neglect due to low values
Costly electronic gremlins
Poor paintwork can be expensive to rectify

Chevrolet Corvette C4 specifications

Sold/number built 1983-’96/358,180 (inc 6939 ZR-1s)
Construction galvanised steel chassis, bulkhead and floor, glassfibre body
Engine iron-block, alloy-head (from ’86) ohv (or all-alloy, dohc) 5735cc V8, electronic fuel injection
Max power 205bhp @ 4300rpm to 405bhp @ 5800rpm
Max torque 290lb ft @ 2800rpm to 385lb ft @ 5200rpm
Transmission four-speed manual overdrive (six-speed from ’88) or four-speed auto, RWD
Suspension independent, at front by double wishbones rear twin trailing arms, lower transverse links, adjustable tie-rods, fixed-length driveshafts; glassfibre transverse spring, telescopic dampers, anti-roll bar f/r
Steering power-assisted rack and pinion
Brakes 11½-13in (292-330mm) vented discs, with servo
Length 14ft 8½-10½in (4483-4534mm)
Width 5ft 10½in-6ft 1in (1796-1859mm)
Height 3ft 10½-11in (1179-1201mm)
Wheelbase 8ft (2443mm)
Weight 3234-3503lb (1467-1589kg)
0-60mph 7-4.7 secs
Top speed 139-181mph
Mpg 15-30
Price new c£26,000 (1984)