gear-head vs petrol-head

Some examples from the web:

• My husband was a gear-head. We had a Mustang.
• My husband was a gear-head.
• You are way more of a gear-head than I ever was.
• Got to say, the whole brainiac, gear-head thing -
• Any quintessential gear-head shall swear by the TAG! Tag Heuer Watches are not the super-expensive, Swiss, ego-boosting timepieces; they are simply for the proper car-loving guy who finds a bit of his own car upon his wrist.
• Technically, Howard's the gear head.
• I have this great money-making idea. I just need a gear head to get it to the finish line.
• Technically, Howard's the gear head.
• I just need a gear head to get it to the finish line.
• A smile is as cheap as that gear head Tram, think of you and me in Fiji with all the money we'll have from this job...
• But can we really trust those gear heads?
• High-rigidity 4-slides base design, super large span and full-gear-type gear head, which is best suitable for low-speed high-torque applications.
• I guess you could say I'm a gear head now.
• I do not recommend installing an exhaust system unless you are a true gear head and are prepared for cutting and welding.
• Computer Chips and Programmers Your truck's computer is technically referred to by gear heads as the Engine Control Unit (ECU).
• Even these are watches that mark their wearers as gear-heads and get their hands on their cars at the slightest chance.
• I GUESS YOU COULD SAY I'M A GEAR HEAD NOW.
• For authentic, pre-loved designer gear, head to the treasure trove that is Garderobe, founded by former fashion buyer Micha Maatouk.
• The only thing - I was scared of was your corrective head gear.
• Apparently, my head gear's a little worn.

Some examples from the web:

• Coburn was one of Hollywood's petrol-head elite, along with Steve McQueen.
• They really are in a petrol-head wasteland, because often as not, they have to drive about in something as slow and dull as this.
• So does this mean it's the end of the road for the petrol-head? Or can you still have fun for eight pence?
• With 20 tracks to race, 9 cars to choose from and a whole host of customisations there's plenty here for the petrol-head to tinker with.
• The world's biggest petrol head...
• You are both big petrol heads despite the Maybachs.
• This, I think, is an interesting debate that petrol heads can have.
• This, I think, is an interesting debate that petrol heads can have.
• This, I think, is an interesting debate that petrol heads can have.
• People like James May and me, petrol heads, we're dinosaurs.
• I know you are what we call a petrol head,
• But if you're a petrol head, you'll find yourself facing a much more important question.
• We've sometimes said on Top Gear that you're not a true petrol head if you haven't owned an Alfa Romeo.
• This, I think, is an interesting debate that petrol heads can have.
• For petrol heads, the Tourneix circuit is 10 minutes away and hosts national car and motorbike competitions and meetings.
• To petrol-heads, 'Mt Panorama' and 'Bathurst' are synonymous.
• I'd like to say you're not a true petrol head if you've never owned a Mini.
• Sharing the wheel with FIA (Federation Internationale de l'Automobile), Polyphony Digital has engineered a finely tuned and accessible game that everyone from casual drivers to petrol heads can enjoy.
• We are again in Emilia Romagna, where between Bologna, Modena and Mantova every petrol head can find his perfect place and where It's easy to find some treasures in the most unexpected of the properties.
• The location, where military and subsequently civil aircraft took off in the past, is now home to one of the largest road-safety training sites in Southern Germany - the ultimate in driver training for passionate petrol heads over a total area of 130 hectares.