Ulster
The Aston Martin Ulster features SOHC 1.5-liter inline four-cylinder with 69.3mm bore and 99mm stroke producing 80-85 horsepower at 5,250 rpm through high-compression cylinder head with 1.75-inch inlet valves, double valve springs, R209 camshaft, Laystall billet crankshaft, domed high-compression pistons, and aluminum-bodied 1.375-inch SU carburetors with dry-sump lubrication. Power increase from Mark II 70 horsepower to Ulster 85 horsepower enables guaranteed 100+ mph top speed with full road equipment through high-lift camshaft and increased compression ratio.
Ulster designation derives from 1934-1935 production period with ten works team cars plus twenty-one production examples establishing most sought-after pre-war Aston Martin racing variant, competing successfully in period motorsport including Tourist Trophy and Le Mans events. The combination of lightweight construction, advanced SOHC valve gear technology, and proven competition pedigree under Augustus Bertelli engineering leadership establishes Ulster among most significant early Aston Martin models, with extreme rarity and motorsport heritage creating exceptional collector value among vintage racing enthusiasts and Aston Martin historians preserving marque competition heritage.