Dallas-based Guiberson Diesel Engine Co.,was to be one of the pioneers of the radial diesel aircraft engine, flying more than 1000 hours with the A-1020 engine. The better-known application was for tank engines, and the Guiberson radial diesel became very well known as a land engine rather than an aircraft engine. The diesel was produced in 1940, and was a 9-cylinder four-stroke air-cooled engine. The engine used direct injection and had cylinders of 5.125" bore and 5.50" stroke, giving a swept volume of 1021 cu ins or 16.70 litres. A compression ratio of 15:1 gave 320bhp at 2200rpm. Cruising rating was 190hp.
Fuel pumps were 9 individual units, with vacuum control, fuel injection pressure was 2200 to 2500lb/sq in. Another engine, the T1020 had a rated output of 250hp and was based on the same design.