First My daughter car strips a Timing belt and does the engine, a week later the replacement car stops exactly in the same spot on the freeway with this noise, we towed but engine will run.. how lucky can a guy get lol
When it runs the smell of Petrol is really strong
http://youtu.be/0xBiKXh3RR0
I am thinking Con Rods or Big end Bearings

That freeway is cursed I tells ya!

Can't help you with that, haven't heard that noise before. Seems worse on the over run, could be big end or loose gudgeon pin from a cracked piston. Autopsy time - remove heads, turn engine over by hand and the problem should be obvious. Maybe remove the sump first and see what is in there? (other than oil)

Sounds like its ready to kung fu sum con rods

Disconnect the accessory belts and see if it's still there - sounds to me like a loose/worn idler or shroud as it seems more sharp on the over run.

I forget to mention that along with the very strong petrol smell it also blows smoke when you rev the motor, not clouds just a light drift of smoke

Well had a new motor and gearbox dropped in and it appears that it was a bearing going going and shortly will go