Which classics still have the potential to get up and go? Alan Anderson remembers the cars, the people… and how to make a classic hot car!

Before the Viva HB came along Vauxhall never really had a sporting image. But, thanks to the efforts of legendry tuner Bill Blydenstein and driver Gerry Marshall, this all changed by 1971 and without their enthusiasm for the Griffi n badge, we wouldn’t have the Lotus Carlton. Today a good Viva is much cheaper than the equivalent Ford Escort and can be made to go just as well – here’s how!

Get one now

Vivas and the later Magnums are much rarer finds than the equivalent Fords and yet are better value. You should be able to fi nd a good HB/HC for around £3000 and ratty ones for much less – the exceptions being the Droopsnoots, GTs and the GP-inspired Brabhams. Rust is the biggest worry, along with an acute shortage of body panels and trim; an Escort remains much easier to own and restore in this respect but mechanically the Vauxhall is presents no major problems.

Hotting one up

There are two engines; the Viva’s ohv design and the later ohc units which went into Vivas and the HC-based Magnums. The former was available in 1057cc, 1159cc and 1256cc sizes, while the ohc engines were 1599cc, 1759cc, 1975cc and 2279cc.

Let’s deal with the smaller units first. Obviously the most logical step is to fit the biggest engine you can find and the ‘1256’ unit can be over-bored to 1350cc, if desired. Blydenstein marketed a different crank to achieve 1500cc. The 1057cc and 1159cc engines were available in ‘90’ tune which meant a Stromberg

CD150 carb, hotter cam, better head and a freer-flowing exhaust manifold (virtually extinct now). The 1256 engine always used the ‘90’ cam (which is hard to improve on, for most road uses), the exhaust manifold plus had even larger inlet valves.

In Chevette tune, the 1256 was as fast as the classic Brabham Viva, which featured twin carbs. This was more a marketing ploy, though, as they are far too large for a 1.2-litre; a 28/36 Weber is a better instrument on this engine, or a Nikki.

Although the head features very restrictive ports, it responds quite well to conventional tweaking and up to 85bhp is on the cards, although the distributor and ignition is woefully inadequate at this level – fit electronic ignition at least.

Real power comes from one of the ohc lumps, although fi tting one in a normal Viva entails a complete new axle, transmission and so on. It can be done, of course, but another option is to fi t the Ford cross-flow lump which, with its gearbox, fits surprisingly well and is a lot lighter than the Vauxhall ohc. Another fi t is the Ford Pinto unit but it’s a more involved swap. Astra GTE engines can be fi tted with ingenuity, too.

Although there are four ohc engines, most folks steer clear of the 1599/1759cc unit because you get more out of a standard 2.0/2.3- litre lump, plus they don’t tweak as well. First step on all is to fi t an evergreen Weber 28/36 carb which will suffi ce for an enormous amount of tuning with new chokes and jets.

The biggest gain comes with a big valve head and, while any specialist can replicate it, there’s still a lot of Blydenstein equipment around (try

Adrian Millar spares in Snetterton). There were four stages, the first pair being simply improved standard heads. while the latter two were better known as Big Valve heads; Stage 4 boasting a higher compression ratio. On a 2.3 engine, with suitable carb and exhaust manifolding 135bhp is available. Incidentally, the HP Firenza yielded 131bhp and the head and cam design was largely pinched from Blydenstein!

Bill was more interested in real world driveability than outright bhp figures and, although he produced hotter ‘GT’ cams, most folks left this component alone, on his advice, as it spoiled this engine’s famed low speed torque. On the other hand, these engines were notoriously asthmatic and unwilling to rev, so a hairier one (along the lines of the Droopsnoot’s) is a good move. If you have a 1600cc or 1800cc engine then the 2.0 and preferably the 2.3 boast a better profile and provide a bit more pep for pennies.

Blydenstein did produce special 2.5/2.6-litre cranks which give modern diesel-like torque figures (210lbft!) but these are rare finds.

But 150-170bhp is on the cards for tractable road and motorsport use. If you want to go further, then the engine from a Lotus Elise/Eclat or Jensen-Healey (pictured) just drops in as it’s based on the Vauxhall block: 140bhp minimum is on tap with much more attainable. Don’t try fitting the Lotus heads on the Vauxhall block as the oil ways are different and it’s a complex fix.

As with the smaller ohv, modified ignition is essential attire. Fuelling is best served by twin Weber DCOEs although the simple 28/36 copes with most road needs reckoned Bill. 

Bear in mind that specialist sports car builder Panther marketed a 2.3 turbo powered Kallista and it went like stink!

Want even more power? As the slant four engine was essentially half a V8, numerous Vivas and Magnums are running around with American V8s, not least the easily attainable Buick/Rover unit which yields around 155bhp.

Let’s talk transmissions! While they all wore four-speed gearboxes, overdrive (as used on the VX 4/90) was available, as was a pukka fivespeed ZF ‘box. This was fitted not only to the Droopsnoot but also post ‘77 VX4/90s and Bedford CF vans from the early ‘70s, but a new hole for the lever needs to be cut. Remember that post ‘73 VX4/90s, now sans overdrive, featured better chosen intermediates as compensation.

There was also a limited slip differential would you believe. Admittedly it figured on the ill-starred FC Series 101Victor/VX 4/90 but the ‘Super traction’ axle worked well – if you can find one now. Other beefier units from the XJ6 and Reliant Scimitar GTE have been grafted on.