Sampie Bosman, Alfa’s de facto motorsport manager in the early 1980s, had been haranguing management for more horsepower, as the 2.5 litre GTV had been battling against larger output rivals for two years. By increasing the bore he had already built a 2.8 litre bent six, which made extra power and torque, but not enough to warrant producing it as a new model. Then it came to light that there was a batch of special cranks, pistons and cylinder sleeves gathering dust at Autodelta in Italy, designed to provide the V6 with a bore of 93mm and a stroke of 72 for a swept volume of 2 934cc. These parts were intended for a car which never saw the light of day because of Italy’s high taxes on large engines. It was Roger McCleery, then in charge of PR at Alfa Romeo, who learnt of these surplus parts while on a media trip to Italy. The bits soon found their way into a prototype 3.0 litre GTV, but despite also fitting larger valves and tubular exhaust manifolds the power and torque was still not quite there, mainly because the fuel injection system was configured for the smaller V6 and could not be easily remapped. Nonetheless, in 1983 a handful of cars were sold in this form. But providence is a strange thing: Alfa Romeo South Africa was having warranty problems with the carb-fed Alfa Six, the alcohol used to boost the octane of Sasol’s fuel being the source of the problem. The solution was simple: whip the Dellorto six-packs off the imported sedans and put them on the GTV – which were intended for track use after all and would run on race fuel. The result was a wholesome 128kW and 222Nm on a modest 9.0:1 compression ratio.
These engines were all built at Auto Unique, Bosman’s business in Booysens. The 2.5 litre engines arrived in crates and left as 3.0 litre units complete with enlarged carbs, branch manifolds and a locally manufactured flywheel. About 250 of the 2.5s were converted in this way. Another problem cropped up when the engine was first installed: the taller intake tract and large capacity air filtration system meant the bonnet wouldn’t close, so Bosman called on the company which had already made the deeper front spoilers (which tamed understeer) to mould a complete fibreglass bonnet with a bigger power bulge. That bulge with its NACA duct has become the big GTV’s trademark, even though it never actually channelled intake air to the filter on production models.
Handsome 15 inch Compomotive rims with their 205/50 rubber are another defining GTV feature; a combination which resulted in overall gearing to make an oil sheik happy. The car shown here now runs a taller diff ratio (from an Alfa 75) and is shod with 16 inch rubber to give it longer legs. It also has an uprated brake booster, increased compression, gas-flowed heads and a beefier clutch. As a 1985 model it has the single piece instrument cluster rather than the quaint split dash with only the speedo ahead of the driver and the rest in the hang-down centre section. According to Bosman around 220 were built (the vast majority in 1984 when 174 were sold) including the race cars, but there are invariably some lookalikes out there too. With local values going as high as R150 000, it isn’t hard to see why the unscrupulous might be keen to pass off the more plentiful 2.5 litre version as the real deal. So, in the same way those afternoons at Crowthorne taught me the danger of mixing the grain and the grape, prospective buyers should do their research carefully if they’re not going to wake up with a headache.