The following is the casting numbers for the crossflow heads along with the combustion chamber volume, combustion chamber shape, and valve size. The crossflow head can use the 1.72 roller rockers found on the Cleveland and 429 heads.
Cast # Volume Shape
C1 47-49 kidney
C2 41-42 closed
D 42 closed
E1 57 closed 1mm larger inlet valves
E2 50 kidney 1mm larger inlet valves
XD-XE alloy heads - 57cc
If the head is not off a XD-XE, it will have a letter and number marked in between #1 and
#2 cyl of the inlet side.. its clearly marked either C1, C1A, C2, C2A, E1, E2 or D..
If you cant see any casting codes, then it is a XD-XE head
MustangSix did a write-up on rebuilding a 250 Crossflow and included some of the differences and similarities between the AU and US 250. A good read:
https://fordsix.com/ams/australian-250-crossflow-swap.50/
Hope this helps
Cast # Volume Shape
C1 47-49 kidney
C2 41-42 closed
D 42 closed
E1 57 closed 1mm larger inlet valves
E2 50 kidney 1mm larger inlet valves
XD-XE alloy heads - 57cc
If the head is not off a XD-XE, it will have a letter and number marked in between #1 and
#2 cyl of the inlet side.. its clearly marked either C1, C1A, C2, C2A, E1, E2 or D..
If you cant see any casting codes, then it is a XD-XE head
MustangSix did a write-up on rebuilding a 250 Crossflow and included some of the differences and similarities between the AU and US 250. A good read:
https://fordsix.com/ams/australian-250-crossflow-swap.50/
Hope this helps