That magazine, whatever it was, seems to prove that we are both right! There was a Tornado Fiat 600 GT but it was not the same as the car we were discussing as it had a Cortina GT engine, not a twincam, and an engine bay rather differently arranged with diagonal reinforcing bars.
Not if you believe this piece of Info I found...
"Ken Smith - Sept. 2, 2009 Its good to see the car again. It's actually a Fiat 600 and made it's first public appearance at the 1964 Blackbush Drag Fest. Built by Tornado Cars it originally had the registration number BOM1 and sported an external radiator bolted to the front. A week later it turned up at Serck Radiators, Park Royal where, after a search of the shelves we sold Tornado a radiator originally made for the Dowty Turbocraft speedboat, small and neat enough to fit inside the front boot compartment, neatened things up nicely. There was a Ford powered Renault Dauphine at the same meeting cobbled together by the Lawrence tune mechanics and a Triumph Hearld bodied Jaguar XK150 that the Downton/Janspeed lads had made. I saw the TriJag some years later on Anglesea, wonder what happened to it? I've come over all nostalgic!"
Ken Smith, whoever he is, was talking about the David Render Twincam powered car.
( responding to the same pic...)
And to me, at this point, he has at least as much credibility as one Allan L...