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Original Modifications

Below is a full list of the basic modifications Ken made to the standard MGB in order to create the first Costello MGB V8 in 1970. Most of these changes were later replicated in one way or another by British Leyland. They are listed by area. Optional Costello modifications are shown in italics and, since they were available at the time the cars were built, and if carried out retrospectively, in's view would not compromise the originality of the vehicle.


Engine Bay


The rear engine bulkhead and inner front wings were re-profiled to clear the Rover V8 and its specially fabricated tubular exhaust manifolds. Bespoke cast alloy engine mounts.


Steering Column


Modified (by Triumph suppliers Torrington) to have two knuckles (universal joints) with the addition of an extra universal joint, also for clearance.




Buick/Oldsmobile/Rover P6 215 cubic inch (3520 cc) V8 in 155bhp tune. Without extra modifications, the available engine configuration at the time necessitated a rather distinctive installation, with a remote centrally-mounted radiator expansion tank and the top hose passing underneath the fan belt. On some blocks, the projection on which the engine number was stamped had to be machined to clear the exhaust manifolds.


Optional modifications were ported and polished cylinder heads, a 'fast road' camshaft and Lumenition electronic ignition.


(In Mk III [1990] specification, a capacity of 3.9 or 4.2 litres was available, together with a standard-fit Costello injection plenum, a K&N air filter, an enlarged throttle body for the larger engine, and a specially mapped Emerald ECU.




Reshaped to clear front cross-member. A cast alloy option was available later.




The radiator was enlarged in capacity and moved forward, the ducting panel redesigned with oil cooler installed beneath and a remote oil filter fitted on the right inner front wing. An electric, thermostatically controlled fan was used in place of the belt-driven original. Later versions used a pair of slightly smaller fans.


Inlet Manifold


Mk I cars used the standard Rover P6 configuration inlet manifolds. For the Mk II, this arrangement was superseded by a Costello cast alloy manifold to take two SU HIF-6 carburettors or one rearward-facing 40 DCOE Weber. A Carter/Edelbrock (now Weber 500cfm) carburettor on a matching cast alloy manifold was optional - and was actually standard on a few Buick-engined cars.


Exhaust System


Fabricated tubular 'block hugger' manifolds by Mike the Pipe, modified big bore MGB exhaust pipes and silencers.  Mike has long departed, but Double S Exhausts in Devon now apparently hold some of the updated V8 tooling and could be worth a call.  These manifolds are more free-flowing than block huggers and fit all iterations of the Costello, but they do require a reinforced aperture to be made in the inner wings.




Bespoke glass fibre with shaped bulge to clear P6 configuration SU carburettors. Later, Mk II cars did away with the bulge after the introduction of new, lower-profile inlet manifolds.




Adapted bell housing, uprated clutch, standard gearbox modified to lock out overdrive in third gear, 3.07:1 final drive ratio (MGC). The Costello five-speed gearbox became optional on later Mk II cars, but few reached customers.


Front suspension


Uprated front anti-roll bar. Uprated lever arm dampers or tubular damper conversion optional. (For Mk III cars, the Costello cast alloy front suspension conversion with tubular dampers had become available).


Rear suspension


A Panhard rod, uprated lever arms or telescopic dampers were optional, as were anti-tramp bars, though Ken didn’t recommend the latter.


Front Brakes


Fitted with high performance Ferodo DS11 pads. A servo was fitted as standard, if not already present. Some later Mk II cars were equipped with optional four-piston Austin Princess or Rover SD1 calipers.

Wheels & Tyres

For cars with bolt-on wheels, Ken used a Dunlop 14 x 5J wheel very similar to that used on the Reliant Scimitar for cars with bolt on wheels. Because they are now more readily available, some people use the Scimitar wheel today, as it is a 5.5J wheel rather than the standard 5J and allows a wider choice of tyres. But they have a different offset and require special wheel nuts. They cannot be mixed with standard wheels and should only be used as a set.

For knock-on wheels, Ken had cooperated with Revolution who produced a bespoke 15 x 5.5 J version of their 5-spoke Classic design with centre-lock hubs. Their use required a little, hardly visible work on the rear wheel arches and could only really be used in conjunction with the Frontline Costello 5-link rear suspension conversion which eliminated the side-to-side deflection of the standard, leaf-sprung setup.  These Revolution wheels are no longer available, but one modern alternative – as used by Frontline Developments on their beautiful LE series of ‘restomods’ – is also a Dunlop branded wheel, similar in appearance to those once used by Jaguar for their racing D types.

You could also go for a classic Minilite wheel, as several of Ken’s customers specified, or one of several brands of Minilite replica – some of which are available as either knock-on or bolt-on versions.




Glass fibre bonnet (as above) on the first 50 cars, bespoke aluminium 'eggbox' radiator grille, Costello V8 badge on the rear panel.  A subtle, but effective front spoiler designed and made by Roger Cook was also an option and is still used on Frontline LE vehicles.

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