MGB Roadster V8

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Legend has it that Ken Costello, race driver and engineer, stumbled across the idea of using the new Rover V8 in an MGB when he spotted one at Pipers Garage in Kent.

So impressed was he with its light weight and compact dimensions, that he acquired a written-off MGB and installed a Rover V8, discovering that despite offering 50% more power, the engine actually weighted 27lbs less than the cast-iron B-Series unit it replaced.

Costello soon realised that there was a potential market for his new hybrid and started to offer conversions from his small garage in Farnham. Distinguished by two bulges in the bonnet to provide clearance for the carburettors, a special Costello grille, distinctive alloy wheels and a prominent Costello V8 badge, they proved an instant success. They drove well, handled neatly and were in many ways the ultimate ‘Q car’.

BL weren’t overjoyed at being upstaged, so in 1973 they introduced their own factory built version, the first few with chrome bumpers, the later cars getting the rubber bumpers fitted to its smaller engined sibling. The sad thing was that they were only ever supplied as a GT, management being concerned that a Roadster would take away sales of the ageing Triumph TR6.

The owner of this car decided he wanted a V8, but only if he could have an open one, so he tasked the Bromsgrove MG Centre with the job of building him one. A 1972 donor car was sourced, the rebuild taking place around a brand new Heritage Shell, work commencing in May 1992.

It was built up regardless of expense, the engine bay being carefully modified to take the wider 3.5-litre V8 sourced from a low-mileage Rover. This was fitted with a 390cfm Holley carburettor on an Offenhauser manifold and Janspeed tubular exhaust manifolds. The engine was mated to an LT77 gearbox and the rear axle was given the tallest available ratio of 3.07:1 for relaxed cruising.

The suspension and brakes were upgraded, the larger wire wheels being fitted with quality Yokohama tyres. Inside the seats were retrimmed in black leather and the dash updated with a correct set of V8 instruments. The file contains a huge number of build invoices, from the £3,659 for the Heritage Shell to £45 for a new clock – everything is there to see.

Although built some 22 years ago, the car remains in lovely condition, 17 old MOTs showing that just over 9,000 miles have been accumulated since it hit the road with V8 power in 1993. Its current MOT expires in June 2016.

It’s a shame that the MGB Roadster had to wait until it was reinvented as the MG RV8 to get proper V8 power, a full 13 years after mainstream production had ceased. This interesting conversion offers the best of all worlds and is available at a mere fraction of the cost of building your own bespoke example.