Unknown block

I am looking for help to identify what has been said to be the following:

mid sixties small block, small journal, 4" bore, high nickle, 2 bolt main 302. The engine has a steel crank with factory numbers but has been no help in identifying the block.
I have some experience in small blocks after owning and rebuilding severl camero's and a Yenko Nova from 1970 but have not heard of this engine. I looked at the casting numbers and they gave no clue as to the stated Rarity of this block. Any help would be appreciated.:cool:

Give us the casting numbers.

I have to retreive them from the shop and will tomorrow. Does this block likely exist and if so is it a rare block?

As far as I know, the following Z-28 engines had 2-bolt mains:
67-68: 389257
67: 3892657
68: 3914678

Some of these motors went into Novas also.

Thanks for the help I will get the numbers and post them shortly