Stop in for a cup of coffee

well I'll be.... found it
B block wedge (1958-1978) [corporate]

Engine Bore Stroke Disp Notes
350 4.0625 3.375 350.0 1958
361 4.125 3.375 360.8 1958-1966 (t to 72)
383 4.25 3.375 383.0 1959-1971
400 4.34 3.375 399.4 1972-1978