We're getting closer. Need to find a date code with the year. I come up with 2 years that the BF code was used, '68 and '69, El Camino (possibly Chevelle and Camaro, too) with manual trans. If it's a '68, it's a 230. In '69, the code was used for a 250. Not sure where you would find the casting date on that block, but if it's anything like the 216/235/261, it may be near the starter.
