GAC Motorsport: Power and Glory

Tucked away in a rural workshop just outside Aylesbury is GAC motorsport. A business that is thriving, but owes its success to a chance pub conversation with a fellow patron about ‘Bump Steer’ in single seater race cars. Chris and Andy went to find out more.

Drinking outside the box

Alan, an agricultural engineer by trade was working as a farmer at the time, but following the aforementioned discussion over a pint or two, was invited to join his new friend Graham in business (back in1993) and together they started GAC.

From Tractors to Race Tracks

“I worked as an assistant manager on a beef/arable farm, after being brought up on my Dads dairy farm in Cheshire Alan tells us. A slight change in direction from what he does day to day now. “I worked in partnership with Graham for 10 years, before becoming sole owner of GAC `15 years ago.” That’s not to say Graham is out of the ‘go faster’ game completely – he just works part-time these days.

Thinking about going fast? 

Whilst my understanding of aircooled engine building appreciates it as an art form, what Alan does is more akin to wizardry. He shows us one of his latest builds, a re-fresh of the 2018 Heritage Parts Centre Formula Vee championship winning motor. “This is a 1300cc single port and we dyno’d it at 108bhp, at 7150rpm”. Those are some serious numbers for an engine that ‘used to’ produce 36bhp!

Rules and Regs…

To put that power figure in perspective, and underline the R&D that has gone into building engines to this spec Alan explains “when it comes to the cylinder heads you can remove material, but you can’t add anything. We can run any VW carburettors, but they must be used with a 34mm restrictive plate.” Alan shows us to a set up he’s been working on.

Getting the right balance 

His preference for fuelling is a single Weber 40 mounted on a bespoke inlet manifold that sits centrally behind the drivers head. I clock the manifold and ask Alan about it. “We tested this set up with and without the balance pipe and found noticeable power increase with the pipe installed.” Needless to say, all GAC Formula Vee engines now have this as standard.

All the gear…

Alan baffles us with his in-depth knowledge with every question we ask. He kindly demonstrates how he uses the flow bench when preparing cylinder heads and getting the optimum from regulation specifications. He taps some numbers into his phone and cleverly produces a potential BHP figure this particular set up could achieve!

Dyno Saw

In an adjacent workshop is Alan’s Dynamometer, complete with soundproofed room, and monitoring station to watch what’s happening at a safe distance. He talks us through the engine that is bolted up “This one, the 2017 runner up, went away last year and another ‘specialist’ decided to fit bigger chokes to up the power. The net result was this car lost 14bhp and we’ve got to now produce new ones for them.” Somethings are best left to the experts…

What’s a SuperVee?

Sat in the workshop is a retro single seater, that’s not seen track action for over 30 years, but that is all set to change in 2019. “This is a SuperVee,” Alan tells us, “They have a 1600cc flat 4 engine, and this one produces 140bhp. This will be running in an invitation class with the historic Formula Fords this year coming.”


We dodge the 4 post ramp, that is home to Alan’s personal Beetle project “I’ve got a Jaguar XJR engine over there to go in this; it’ll be mid-mounted”. Those words flow effortlessly from his mouth as if he’s just told us it only a needs a quick wash and it’ll be done. Nothing seems to faze him. Which I guess is why he designed, built and sold his own Formula Vee chassis for 10 years – a car that claimed 5 out of 8 UK titles between 2006 and 2014, always powered by his engine too.

Up in the roof

Sat miraculously on the mezzanine floor is a GAC race car that used to compete, and win, in Formula Vee in Germany. “This series allowed for spoilers front and rear too and had a 1300cc watercooled engine – I’m currently working on a 1400cc 16v version, but sadly there’s no series to run it in these days.”

Strip Expertise

GAC doesn’t just build engines for circuit racing either. His name is big news in the UK air cooled drag racing community with a number of well-known cars relying on GAC when the lights go green. He gives us a couple of examples of builds he has done – one project will see 800bhp by the time he’s finished!

Statistically Speaking

As we start to wrap things up, we get Alan to run us through his circuit successes and quite honestly it’s amazing. GAC engines have taken the title for the 5 of the past 8 years, and 15 times in 26 years and in many cases the runner up position too.

Whilst, not a racer himself, Alan is hugely competitive, and it definitely is all about the power and the glory – he’s in it to win it!

You can catch the Heritage Parts Centre Formula Vee Championship at the following UK circuits and stay tuned to our Social Media for the chance to win free tickets.

Brands Hatch – 13/14th April

Mallory Park – 5th May

Anglesey – 15/16th June

Snetterton – 6th July

Silverstone – 10/11th August

Donington Park– 7/8th September

Oulton Park – 5th October


Heritage Parts Centre delivers quality parts for VW and Porsche enthusiasts worldwide. Check out our car parts website here and follow our fun with #driveheritage on social media.


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