C8AE-H
1968 360/390/428cuin heads 2.02" intake 1.55" exhaust.
The intake looks like a 390 4V intake.
a 428 intake has larger runners with softer outside edges.
The date casting will be between the
oil adapter and where the pan bolts up.
might start with an 8 if the block matches the heads.
something like 8A12.
Casting number is on the front paasenger side of block.
C8AE-A
C8AE-C
C8AE-E
Any of these three number will narrow it down to a 360 or 390