Complex sentence: Earlier model AT-6/T-6s re-built between 1949-1953 with improved cockpit layout, increased fuel capacity, steerable tailwheel, updated radios and a 600hp R-1340-AN-1 engine.
Split into simpler sentences: Earlier model AT-6/T-6s re-built between 1949-1953. They have improved cockpit layout, increased fuel capacity, modified landing gear with steerable tailwheel, updated radios and a 600hp R-1340-AN-1 engine.