RE: World Model Speed record???
Hmm, 343 kmh = 212mph. Not bad for a piston engines plane back in the 70's. Most FAI or F1 pylon planes are easily capable of these speeds if not more in a straight line. As for turbines, I'd say easily exceeded.
Maybe you missread the units?
Regards,
Tony
(was a member of the team who set the Guiness record with the bandit)