"Long range" tanks are a bit misleading by todays standards. The old 6-pot Rolls-Royce 172s only had 39 Gals (36 usable) and were fairly limited in safe flight hours. Many ordered the long range tanks, so many they soon became standard. I know the club operating Rusts 172 during these days and they got long range to be able to do extended xcountry flights. Btw, it was not the only GA flying west-east behind the iron curtain, but the second. In 1971 a strange story went through media of a 172 fleeing into GDR and a dubious western soldier asking for sanctuary in that case. I heard rumors Rust got a FAA lncense again later, can anybody confirm?