There are seven HC coded combinations:

1969 Camaro 250hp 350 L-65 manual trans 2bbl carb
1969 Chevelle same as above
1969 Nova same as above

1965 Impala 250hp 327 powerglide L-30 1x4bbl
1966 Impala same as above
1967 Impala same as above but 275hp 327
1968 Impala same as above but 275 hp 327

However the block casting 3892657 indicates a 1966 or 1967
block

The head number is not in my book but there is a 3932441 that is
a 67-69 327 head with 76.3cc 152 cfm intake 93.2 cfm exhaust

mike in tucson