C1AE-A'a are 61-63 352/390 heads with 71-74cc chambers and the C6AE-B's are probably C6AE-R 352 heads with 71-74cc chambers. Both heads have std size valves and lowriser ports 2.34"x1.34 int, 1.84"x1.34" ex. There are no "B" castings in the C6AE numbers. There are however C6TE-B's that were truck heads. Same chamber, port and valve size as the others.

G.