block casting #

I've got a line on a 455 but not sure what year it is. The casting number is 1241735, can anyone out there tell me what year it is from that number? I know there's a letter code on the block, usually has that info. in a Chiltons Man., but I haven't seen the motor yet, just a picture. Thanks.

Gary G.

 

That casting number was used 72-75. You will need the additional info to pin it down further.