And here are Ken's answers to earlier questions submitted by email to the website:

Harry Irvine: Have you any idea of how many roadster MGBs were converted in the early 1970's compared with the MGB GTs? Also, was the total number of conversions around 200?

A: Sadly, the relevant paperwork has long gone, but as near as I can remember, some 225 cars were produced with a ratio of about 6 to 1, GTs to roadsters.

Alun Evans: I have the original radiator expansion tank on my car and I wondered whether they were fabricated or whether they came from Rover? I have a small split developing at the neck of the unit and, although I could get it braised, wondered if they were available anywhere?

A: This type of expansion tank, as fitted to the early cars, was specially fabricated. There are none available now and I suggest brazing the split or having another tank made. The positioning of those tanks was not ideal, but the configuration of the then available engines left me little choice. I subsequently used standard MGB expansion tanks - as you could too - if you acquired later model alternator brackets. This would lower the alternator and provide a more conventional path for the top radiator hose.

Peter Hollis, South Africa: Regarding the single 40 DCOE on your 90 degree manifold, what are the correct specifications for the jets, valves, emulsion tubes, venturi, etc? I am struggling to tune my car correctly, as these settings seem to have changed during the life of the car. Knowing the original specification would be a huge help.

A: The 40 DCOE Weber settings are no longer to hand and you are asking a bit much of my memory, so I am indebted to Iain Barraclough for the following suggested settings. They are for a Rover 3.5 litre V8 engine in standard tune:

Slow Run Jets - 40F8

Main Jets - 130

Emulsion Tube - F2

Air Corrector - 170

Accelerator Jet - 55 (60 is richer)

Accelerator Return Valve - 0

Float Chamber Needle Valves - 225

Main Venturi - 30

Auxiliary Venturi - 4.5

Sven Nielsen, from Denmark, wanted the equivalent information for the 45DCOE now fitted to his 3500cc roadster. Here I must thank Webcon UK, arguably the world' s largest distributors of Weber carburettors and parts, who (as with any carburettor change) also advise fine-tuning on a rolling road. "Standard" denotes the ex-factory settings:

Slow Run Jets - 55F8 (standard)

Main Jets - 160

Emulsion Tube - F2 if needed or F16 (standard)

Air Corrector - 155 (Standard)

Accelerator Jet - 55 if needed or 45 (standard)

Accelerator Return Valve - 0 if needed or 40 (standard)

Float Chamber Needle Valve - 225 if needed or 200 (standard)

Main Venturi - 36 (standard)

Auxiliary Venturi - 4.5 (standard)

Several owners have also asked about underperforming fuel pumps, particularly elderly SUs.

The standard-fit SU fuel pump can be reconditioned and/or fitted with an electronic module (recommended) to replace the less than reliable points. The SU part number for the original pump, which delivers 14 gallons per hour (gph), is AZX 1307, with the suffix EN denoting the points-free version.

Burlen Fuel Systems, now the holders of the manufacturing rights for SU products, offer reconditioning/exchange schemes for all their carburettors and fuel pumps.

Good alternative fuel pumps of higher capacity - which will be required in the case of 4-barrel downdraft carburettors like the Weber 500cfm - and in my opinion, with any engine producing in excess of 180 bhp - include those made by Bosch, Sytec and Facet. You will need a flow rate of around 20 gph, and an adjustable fuel pressure regulator, such as an Alpha or an FSE, is recommended -  set to 3psi.

Oliver Marchant: Oliver had two queries. Firstly, he has Rover exhaust manifolds (presumably cast) which foul the steering column and he asked for a solution.

A: There are two alternatives: the best, from a performance point of view would be RV8 manifolds or Frontline Costello manifolds, though the latter are currently out of production. However, using either of these involves cutting holes (a la original RV8) through the inner wings. The other alternative would be to use the kind of tubular 'block-hugging' manifolds which were originally produced for me by the famous 'Mike the Pipe'. These do not involve bodywork modifications, but Mike has long gone, as has the business which succeeded him, and the jigs have disappeared. (However, Ken's research leads him to believe that manifolds of a very similar pattern are now available from the MGOC and MGB Hive, in the latter case either separately, or as part of a full stainless steel system - LW).

Oliver's second query involved finding reproduction Mk I Costello V8 badges. None have been made since the early seventies as the patterns no longer exist - nor would new ones be authorised. There are enough fake Costellos about already! Mk II V8 badges, however, which are engraved, have been reproduced, but quickly sold out - to registered Costello owners only. A second batch has now been produced so if you fancy one, drop Lawrence a line. (December 2009)

Q: Wouldn't an MGC have been a better starting point for building a Costello V8 than the MGB?

A: In some ways, installing a V8 in an MGC was easier than doing it in a B, although I only tackled two of them  -probably circa 1973. Perhaps if the owners did a search of the DVLA records, that would reveal the date of the engine change and therefore of the build.

Why was it easier? For a start, in order to fit the bulky 6-cylinder, 3-litre engine, British Leyland did away with the front cross-member in the MGC, which also helped me with clearance problems at the front of the V8. The cars already had a bonnet bulge, larger 11.06" front discs, 15" wheels, a larger radiator, a stronger gearbox (later fitted to Bs as well) and the desired 3.07:1 rear axle ratio. They also had torsion bar front suspension in place of coil springs, with telescopic dampers instead of the B's rather archaic lever arms. I had to re-rate the front torsion bars and dampers to accommodate the lighter weight of the V8 and also create different engine mounts - apart from that I had to do very little that hadn't already been developed for my MGB V8.

I hear that the ever-persistent Lawrence has now actually flushed out one of the two MGCs that I re-worked. It now appears to have had a rear suspension transplant, but it wasn't done by me, and I can't vouch for any modifications - let alone such radical ones - that were outside my control.

Tempting though it might have initially seemed, I chose not to graft Jaguar rear suspension onto any of my cars because it was a major engineering project and more trouble than it was worth. Besides, I think the Costello 5-link rear suspension works better, is more cost effective and more in keeping with the car because it retains the original back axle. So it follows that the Jaguar equipped MGC must have been modified again after it left my hands and is, sadly, no longer completely original.

However, it's an inescapable fact that many Costellos have been further modified over the years and to exclude them from the ranks on those grounds would probably leave precious few. Nevertheless, though I am perfectly happy with the likes of Holley carburettor conversions because they were already widely available for the Buick engine from which the Rover was derived, I do have reservations - as expressed above - about the unapproved 'Jaguarization'. Others may disagree, but I think it's a step too far.

That said; my policy has always been one of continuous development, which is why all Costello upgrades, apart from the Mk III injection, are designed to be easily retro-fittable. But what I always tried to do - as Frontline also does with Spridgets - was to limit my parts selection (apart from the components I designed and produced myself) to those from the original manufacturer, MG. As they might say these days, in order to 'maintain the original DNA'.

Why did I not convert more MGCs? Firstly, because I wasn't asked to. And secondly - even allowing for the relative ease of the conversion - because the MGC was significantly more expensive than the MGB in the first place, it was not really a viable proposition financially.

TechTalk with Ken

Email Queries

Some of these questions were submitted via e-mail in 2008 whilst the website was still a fledgling operation. They too are now answered more fully, as are a number of more recent queries.

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