Some 52,000 sports car fans from a dozen or more states and several foreign nations were thrilled and broiled Sunday and Monday afternoons at the Grand Prix Road Races at Garnett. The spectators began pouring into the park early Sunday morning, establishing their cars, trucks or umbrellas at strategic spots about the 2.84 mile course which encircles Lake Garnett. The Sunday races were marred by the death of Ed Garner, 29, Collinsville, Okla., whose M.G.A. crashed into a utility pole after spinning off the cork-screw turn. Cars entered represented the cream of the sports car world: Ferraris, Maseratis, Porsches, Spyders, Elvas, Lotuses, Corvettes, M.G.A.s and several others. Gov. and Mrs. George Docking and representatives of the French, German and Italian consulates attended Monday.