According to Chevrolet By The Numbers:
3963512:
1969 (mid year)
2-bolt = Passenger 335, 390 or Corvette 390 h.p.
4-bolt = Corvette 400, 430, 435, Chevelle 425 (COPO), or Camaro 425 h.p. (COPO)
This block was used from October 1968 ('69 model) through the 1971 model year. The book also mentions it being used in the 454 (my book only goes through 1969. So, I don't have later data). But the 454 began in 1970.
If you have the head casting numbers and dates, that helps narrow down the application. Though, it might not get any better than this w/o crank and cam specs...
F16 decodes to June 1, 1966. So, you may want to check that code more closely. It should be after Oct. '68: ~J18, K, L, etc...
You can check to see if it is a 4-bolt w/o dropping the oil pan by looking above the oil filter boss. The 4-bolt blocks have drilled and tapped external oil cooler bosses above the filter. The 2-bolts have holes there that aren't drilled completely and don't require plugs.
