The Helio H-370 was the first attempt to add turbine power to the Courier. A standard H-250 was re-engined with an Allison 250-B15G turbine for testing in 1969. It found little performance benefit and increased fuel consumption. Instead pursuing work on the aircraft the company decided to focus on the purpose built H-550 turboprop Helio Stallion. N6309 got it's piston engine back and became the pattern aircraft for the HT-295 tri-gear Super Courier. The nose gear equipped Courier was developed from a request by the Mexican Government and the aircraft was exported to Mexico as XA-SEW in 1973.