Had the seated hardened when I bought them off a machine shop going out of business.. They were bare heads on a shelve ,,
I bought them done and ready to go .
The block is large journal.. And the casting was used for 302-327-and 350 in 1969.
So I guess I could even build a 302 .. If a person could find 302 flat tops .
Or 283 - 125 over