identify numbers for me on engine and heads

[shaggyfinisher]

the block # is 41h918525 (where are the letters on the block located?) the heads #1237661 thats on both heads one has a big 2 above those # the other a big 4 with c19 and c8 thanks in advance for any help thats provided Steve......... I have a couple more that I will need help with

[flynbuick]

It is a 455 from a 1971 Riviera. The lettersr will be on the deck right beside the dipstick hole. The heads are March 19 and March 8 1971 respectively.

[shaggyfinisher]

thanks very much Steve