383 Build up questions...

When I picked up 2 383's both from 68 Newports they each had the following heads;
2951250 (1968 440 heads) (440 1968 2.08 1.74)
Why they come up as 440 heads I dont know but these appeard to be original on these engines. Iended up picking up 4006452 heads for them as they have the hardened seats and flow well.