http://www.hagerty.com/price-guide/1965-Buick-Skylark Hagerty.com] History of the 1964–1967 Buick Skylark - Retrieved on 07/22/2013 The Gran Sport featured Buick's 401-cubic-inch-V8 with a Carter 4-barrel carburetor that produced 325 horsepower at 4400 rpm, listed as 400-cubic-inch in sales literature to elude a General Motors limit of 400 cubic in intermediate-sized cars.