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Big Healeys

Published: 10th Sep 2014 - 0 Comments - Be the first, contribute now!

Big Healeys
Big Healeys
Big Healeys
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In standard form a Big Healey is hairy enough – but tune yours right and it’s a real roadburner that’s also manageable

It’s the original British Bulldog and a true hairy-chested sports car which has to be taken by the scruff of the neck and shown who’s boss. There’s nothing like a Big Healey when it comes to good old-fashioned driving fun and with a few well chosen mods you can make yours, faster, smoother, safer and even more desirable to take out for a spin or a spot of club motorsport.


First thing is to check out the chassis. Ensure the main rails are straight and strong. Periodically inspect at the B posts and behind the sills – mud becomes trapped around the chassis outriggers. Also check the condition of the inner wings, floorpan and bulkheads. These are stressed sections welded to the chassis and can thus be considered integral to the car’s strength.

Mechanically these sports classics are as strong as an ox but before any tuning and improving is carried out, it’s best to spend some of that budget on making the best out of what you already have; Healey specialists say it is very surprising what a good service and sort out can achieve, especially to items like the steering and suspension. If the engine is beyond repair, replacement C-series blocks can still be found from breakers, since these were also fitted to the bread-and-butter BMC saloons of the time, such as the Westminster. Other parts such as upgraded cylinder heads are available from respected specialists such as AH Spares.


As the final Healey enjoyed 50 per cent more power than the original 100/6, the most obvious approach for early cars is to fit the factory upgrades, right up to the 148bhp tune if you wish. This means the post 1957 cylinder head and after that a 3000 spec engine is a worthwhile swap for the original 2.6 unit.

Other factory methods to improve power includes triple carbs and the uprated 3000 MkII camshaft where the total gain should be somewhere in the region of 30 per cent; the better MkIII camshaft improves this even further.

MkIIIs reverted to twin SUs albeit HD8s rather than the HD6s. It’s entirely possible to combine MkII and MkIII set ups to create a unit with three HD8s.

John Chatham is well known in Big Healey circles and knows just about everything there is when it comes to tuning; he has recently remanufactured the alloy engine blocks which were originally homologated for competition purposes. It’s the ultimate for sure, but these alone cost some ten grand while £30,000 rewards the owner with a full race-spec engine pushing out over 250bhp, claims Chatham. But you needn’t spend all that!

A good upgrade includes an alloy head (which apart from its efficiency also cuts a lot of the car’s nose weight), sportier camshaft and six branch exhaust, which with a triple carb setup should provide an honest 200bhp plus from an engine costing one third of a race spec unit that’s road usable, too.

Rawles Motorsport advises an electronic Mallory distributor, lightweight engine plates (to remove some of the excess weight more cheaply), and a ported, gas-flowed head for starters but advises sticking with twin carbs for servicing ease. “We’d also fit twin SU HD8s, not the triples but the key thing is to set the cars up on a rolling road like we have, as that way you’re getting the optimum performance from the engine”, it says.

Denis Welch Motorsport offers a whole range of go-faster gear, including a range of alloy cylinder heads for around £2000 – a similar outlay buys you a set of triple Weber DCOEs, which incidentally, is not that much dearer than a trio of SUs. JME Healeys provides a similar selection of upgrades but warns owners not to go overboard and fit parts which can’t be converted back to standard trim and devalue these rapidly appreciating cars. An ex Hopkirk works Healey, drinking via a trio of 48 DGOE carbs, produces 210bhp. Good for 130, it gives you an idea of the potential that still lives within the 2968cc engine.

If the engine is clapped out and needs a rebore, you can stretch the above capacity further using Cosworth pistons at £800 for 3.3 or 3.5-litres and more torque. If the crank is shot, then a competition type that’s been Nitrided can be used. But at almost £3000 it’s only for the dedicated. A far more useful upgrade is a better oil pump for £175 (a spin-on oil filter conversion is also a worthy fit) and an improved radiator; Rawles sell uprated radiators for £287 on an exchange basis. Ditto aluminium sumps are also available to aid cooling as well as providing a bit more stiffness to the block.

Even if you intend keeping your Healey pretty standard, when carrying out a clutch change it’s still not a bad idea to give a lightened flywheel some thought as it greatly aids throttle response. The best solution is to fit an aluminium item, but this typically costs almost £500; a cheaper route is to have your one skimmed.


If you intend to keep your Healey and want the best then why not start with a brand new chassis for stiffness? Costing from £3950 (Denis Welch Motorsport), but it’s possibly the most worthwhile thing you can do as it will be rot free and stiffer.
AH Spares has developed a strengthened replacement, which includes inner sills and the main floor pans, costing from £4150.

Big Healey legend John Chatham believes a few simple upgrades to a good chassis will transform the car going back to a bare chassis, strengthening the suspension mountings (as like the Works cars), before fitting an uprated front anti-roll bar, and springs. JME Healeys advises better dampers poly bushing (Touring types) but not to lower the car as Healeys are low enough! And while sophisticated rear end set ups using telescopic dampers are available, they are only necessary for dedicated competition use, it adds.

The braking system sufficed, with discs at the front of all 3000s and an optional servo on 3000MkIIs, standardised for MkIII. Kits can be bought to convert 100/6s to discs – and fit EBC Greenstuff pads as a direct replacement for the originals – while Lotus Cortina discs were a good upgrade – if you can now find them. Standard rear drums are adequate.

The steering is always going to be heavy on a Healey and if it’s too much of a chore then you can either fit a dedicated rack and pinion kit from Rawles at £6000 fitted or an electric add on for half this to the existing set up. If you like the standard tiller you can simply have it overhauled – which makes a big difference – or add an improved Dennis Welch set up which can also include a higher ratio for sharpness.

In standard form the Healey used a four-speed gearbox with overdrive and if in good order is entirely satisfactory. A sturdier clutch on post ‘62 cars can be obtained cheaply by fitting an XJ6 cover along with a Land Rover SII/SIII, we’re reliably informed.

Straight cut gears with improved ratios (Denis Welch, £895, Tulip or Sebring spec), and an uprated overdrive unit (£282.50 from AH Spares) are the next steps. You can go five speeds if you wish, where the ubiquitous Sierra Type 9 can be used, but for this big beefy engine the Toyota Supra ‘box is the better all rounder. However at £4000 (from A Head For Healeys) it’s rich fare but Rawles sells a kit (sans gearbox) for £1800. JME prefers to just fit a higher axle ratio for more relaxed cruising such as a 3.45:1 unit. A Quaife limited slip diff is available from John Chatham Cars, costing £1014 it’s a worthwhile upgrade, especially if the original is getting tired.

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