Chevy Brooklands

The  5.7 Litre Big-Torqueing Capri

Finding a clutch and gear lever rather tedious work, my ideal car has always been a big-engined, automatic coupe.  To me, what is all-important is what happens when the accelerator is pressed while driving between 20-50 mph in top gear, which is a lot of the time, and where acceleration is useful.  Most cars, even my turbocharged 2.8i, respond with only a stretch and a yawn. 

It is all about mid-range and bottom-end torque, or the lack of it.  Few non-American cars have very much.  For low-down torque, turbochargers, superchargers and variable valve timing notwithstanding, there is still no substitute for cubic inches.  To appease the great gods Emissions and Fuel Efficiency, manufacturers have stuck with small engines and multiple valves, which actually reduce low-end torque.  Power is plentiful at the top end where it is practically inaccessible with an automatic. The few big-engined exceptions, like the XJS, are such heavy and cumbersome cars that the advantage is lost.  Using kick down is a clumsy extreme, like kicking someone out of bed just to wake him.

Tickover's Chevrolet 5.7 litre V8 conversion for the Capri promised everything I ever wanted on a plate, with extra helpings.  It even comes complete with automatic transmission as standard.  For modest cost, here was a car which should, in response to the throttle, pick up its skirts and go like the proverbial bat out of Hell.  Some 70 million of these engines and transmissions were made over 25 years, so parts and accessories are inexpensive and widely available.  Obviously, a few extras are needed, like stronger front springs, a larger radiator and a special propshaft and exhaust.

Two versions are offered, 300 and 400 bhp, with various optional extras.  On both, performance camshafts, manifolds and other tuning parts are fitted to boost the output of the rebuilt pushrod engines, which per litre was modest in standard form.  Both run on unleaded petrol.  The 400 is lumpy at idle, the extra 100 bhp coming in a precipitous peak around 6000 rpm, but the former suffers no loss of tractability and can easily pull away from rest in top.  With 360 ft lbs of torque @3000 rpm, a gearbox is almost unnecessary!  Breakerless electronic ignition is an option, so the only real, retrograde feature is the carburettor (which needs minimal maintenance) and a manual choke.  Weight is increased by only 130 lbs (like having a small, invisible man sitting on the bonnet) so handling and braking should not be affected much.

The Capri Club provided the donor car, a reasonable E-reg. 280, which after a makeover at Duffy Motors was delivered to Bexleyheath.  It was Tickover's eighteenth Chevrolet conversion, and their first on a Brooklands.  For everyday practicality I wanted the car to be as quiet, refined and inconspicuous as possible, so some variations on the normal 300 bhp conversion were specified.

The 2.8i back axle can handle the extra power, but with the 3-speed automatic the car is left under-geared, redlining at 130 mph, far short of its potential top speed.  No higher pinion set is available for the Capri axle, but the Mk II Mustang axle is a straight swap, being the same length.  With its 2.78:1 differential and 205/50x15 tyres gearing is raised to 25 mph per 1000 rpm, just enough to reach the magic 150 mph, and peak engine torque comes at 75 mph for relaxed motorway cruising.  The 205 tyres increase gearing by only 2% but every bit helps, whilst a little more rubber protects the wheel rims.  New polyurethane suspension and steering bushes were fitted all round.

Tickover normally fit a 'twin turbo muffler' exhaust, with a single straight-through silencer each side.  For the Brooklands, they built a large-bore double, triple-silencer system using conventional boxes to keep noise down to standard levels without significant loss of power.

The conversion was completed in 8 weeks.  What impressed me was how neat the installation was - the Corvette engine just drops in, with no bulge in the bonnet and everything easily accessible.  The radiator and thermostatic electric fan fit in the front void (normally wasted space) with a slight modification to the bay.  Rumour has it that the Capri was designed to take Ford's own 5-litre V8; so even on the V6 models the compartment is under-filled.

Apart from the 2" tailpipes, plain tailgate and coachlines, the car is outwardly standard.  Nevertheless, the insurers insisted on a Thatcham Category 1 alarm/immobiliser from an approved installer, so the final stop was Auto Audio Installations in Shepherds Bush, who fitted Meta electric windows and central door locking at the same time, so all could be integrated and operated by remote control.  A single plip closes the windows, locks the doors and sets the alarm.  Unfortunately the tailgate lock and sunroof could not be included.

So, how does it go?  Turn the key and the engine starts with a Meccano-like wail then settles to a steady tickover.  When moving the selector into drive, a foot must be firmly on the brake to restrain the strong transmission creep.  Unlike the injected 2.8, the accelerator has a long, linear action, and when depressed to the customary degree, progress is steady rather than spectacular.  Around town, with its slightly lumpy transmission and general mechanical unrefinement, the car has a solidly 60's feel, of belonging to an earlier generation than the 2.8.  Like most older automatics, the transmission habitually up-shifts on the overrun, so the brakes must work hard.  With the harder bushes and coil springs, handling is firm and taut, and the ride less absorbent of bumps and potholes, while the heavier back axle thumps loudly over speed humps.  However, at speed everything smoothes out and quietens down, and fast progress is effortless, the overall gearing feeling just right.  On bends, the car feels well balanced with little body roll or float.  When the throttle is floored, at any speed, in any gear, the exhaust's soft woofle transmutes into the inimitable V8 throb, and Brooklands leather shoves deeply in the back.  The acceleration is not quite compatible with the claimed 0-60 in 4 seconds, but fast enough to shrink most things in the rear-view mirror to a dot.  

All conversions have their drawbacks.  The Chevrolet transmission has no electrical contacts, so a manual switch is needed for the reversing lights, and the engine can start in gear, so care is needed.  On the plus side, the car does not overheat, quake on idle, stamp its feet, wag its tail or loose traction even on full power.  Costs?  The insurance premium is just 15% higher than for the standard Brooklands, but petrol consumption, touring, is a hefty 17.5 mpg, offset slightly by the cheaper unleaded price, and with too much showing off it could well plummet to single figures.  But, as a supercar, the Chevvy Brooklands is a bargain; it's two-thirds of an Aston Martin V8 for a fifteenth of the price.  And it's unique.