Thanks "C":
I will pass this info onto my friend. If this helps, the heads are 3890462, Camel Hump with a casting date of B046, Feb. 4, 66. He does not know if these items are original to the block since these two items are pretty interchangable on the small blocks. But based on your statement regarding the oil fill tube, it would seem the block has to be a 68 or before if I understand correctly.
I will have him check and see if he can read or find any numbers on the back side of the manifold. To answer your other questions,
The manifold is cast iron, and it is a Q-Jet carb.
Thanks for all the info and help!!!!!!!!!!!!!!!!!!!
dab67