Mark 5

Bolwell Cars demonstrated that it had made the transition from a backyard business to a serious specialist vehicle manufacturer with the release of the Bolwell Mk5 in late 1964. Although sales of the open top Mk4 were still going well, Campbell Bolwell wanted to move forward by putting into place some new design and manufacturing concepts, new marketing ideas, and so on. He achieved this with his Mk5 model, which cost ₤330 for the body-chassis kit, and which was variously advertised as “It only looks expensive”, “…this car does not cost ₤3,441!” and “A device for making dreams come true”.

One of the prime motivators behind the Mk5 was that the design purist in Campbell always had difficulty with the concept of owners fitting a large, heavy 6 cylinder engine in a car that had been designed for a light-weight 4. Not only did this potentially upset the balance of the chassis and suspension, it also necessitated ungainly and sometimes ugly bonnet bulges.

The pragmatist in Campbell (and perhaps the marketeer in him as well) also realized the opportunities of appealing directly to the 6 cylinder Holden owner. In fact, Campbell has jokingly referred to the target market for the Bolwell Mk5 as “sports car enthusiasts and owners of rusty Holdens”.

By the time that Bolwell released the Mk5, there were over a million suitable Holden “grey” engines out there somewhere and the FX/FJ models that Bolwell suggested as being suitable donor vehicles were likely to be at least 10 years old and thus quite affordable.

The Mk5 chassis was therefore designed to suit Holden engines and suspension with much of the other componentary in the Mk5 also sourced from Holdens. With such widespread availability of second hand Holden engines and other parts, Bolwell Cars was able to target a much wider audience for the Mk5 model. To some extent this offset the price increase from ₤198 for the Mk4 to ₤330 for the Mk5, although both models were offered as quite distinct choices to prospective Bolwell owners for a considerable period of time (the Mk4 was not pensioned off until 1965 after selling some 100 units).

The overall design was still in tune with the swoopy profile of the earlier Mk4 models, but with the front being much smoother and very definitely influenced by the popular Jaguar E-Type. The large and somewhat bulbous rear window (subsequently described as offering “panoramic visibility”) appears similar to that of the Jensen Interceptor, however the Jensen wasn't released until two years later so it is just a case of parallel evolution. The Mk5 body was fibreglass, with thickness depending on the stress of the area. Dashboard and all inner stress members were bonded into the body. The Bolwell brochures described the revised body as, “a strikingly individual and glamourous shape. Notice the smooth sleek lines of this thoroughbred. A car that would surely would not look out of place in any surroundings”.

The chassis was described in the Bolwell brochure as “a backbone back-bone type unitary constructed chassis made from rustproof, light gauge spot welded panels”. It was steel plate, like the Mk4B, but with a bit of tube in it to pick up the suspension. It was spot welded and cut, bent and folded in the Bolwell factory. The chassis incorporated the footwells, front and rear inner guards, transmission tunnel, luggage compartment, cockpit sides and floor. In keeping with Campbell Bolwell’s sports car design theories, the chassis was designed so that the engine was mounted well back from the front cross member in order to improve front/rear weight distribution.

Brackets and mounting points were provided for other components including Holden engine and gearbox, tail-shaft (which required shortening), rear suspension (with some leaves removed), front suspension (without coils and steering), wheels and tyres, radiator, battery, electrical components including voltage regulator, switches, interior light, instruments, fuel tank and so on. FX and FJ Holdens were considered to be most suitable donors, although the hydraulic pedal unit from an FE or FC Holden was recommended. Basically the only non-Holden components used were a modified Morris Minor rack and pinion steering set-up and front coils from a Standard 10 or Austin A30 (or similar) to replace the standard Holden coils. Bucket seats from a range of vehicles, including Austin Sprite or Hillman Imp could be used.

All up, a completed Mk5 was estimated to weigh approximately 12½ cwt and to have a top speed of around 125 mph depending on engine tune and rear axle ratio. Performance and handling was largely up to the skills, and budget, of the owner. Certainly there was no shortage of “hot up” parts available for early model Holdens, including extractors and sports exhaust systems, carburettors, modified heads, and so on, and there were plenty of workshops around to modify or tune your engine if you couldn’t do it yourself.

Bolwell advertising for the Mk5 suggested that a complete Mk5 could be built for an all up cost of around ₤500, and went on to suggest that this would produce a car with a resale value far in excess of this. If you couldn’t do it yourself, Bolwell advertised, “Drive in your old model Holden and we will construct your finished car using your components - ₤650 tax paid.” At one stage Bolwell also offered “a complete finished car registered and ready to drive away – P.O.A.” but this was problematic and reasonably short-lived exercise as a result of Bolwell Cars fighting a losing battle with the Australian Taxation Office.

Bolwell sold around 75 of the Mk5 model and provided sufficient profits to fund the development of future models of Bolwell Cars.

Bolwell Mk 5 – Dimensions and Specifications
(Sourced from Bolwell promotional material)

DIMENSIONS:
Wheelbase90” (2286 mm)
TrackDepends on model of donor unit
Overall Length158” (4013 mm)
Overall Width66” (1676 mm)
Overall Height43½” (1104 mm)
Ground Clearance6½” (165 mm)
Weight – Kerbapprox 12½ cwt (635kg)

SPECIFICATIONS:
ChassisBackbone type unitary chassis made from rust-proof, light gauge welded panels
EngineHolden FX or FJ “grey” engine recommended
TransmissionHolden FX or FJ recommended
SuspensionHolden FX or FJ recommended
SteeringModified Morris Minor rack & pinion
BrakesDepends on donor unit
WheelsDepends on donor unit
TyresDepends on donor unit

PERFORMANCE:
Standing Quarter MileStandard Engine producing 75 bhp – 17 secs
Modified Engine producing 120 bhp – 14.9 secs
0 – 50 mphStandard Engine – 7.5 secs
Modified Engine – 5.0 secs
Top Speed At LeastStandard Engine – 100 mph (161kmh)
Modified Engine – 125 mph (201kmh)

COST:
$660.00  Body/Chassis Unit
$20.00  Proof coating of full metal underbody, inside tunnel and engine bay
$4.00  Tinting of Rear Screen
$13.00  Roll Bar Fitted
$70.00  Full exterior painting
$35.00  Full wiring of car
$136.00  Supply reconditioned FJ engine, gearbox and shortened tail shaft
$98.00  Fitting of major Holden components such as engine, gearbox, front & rear suspension, petrol tank, shock absorbers
$40.00  Special strengthened chassis version of Mk5 for use with larger engines