I have been trying to authenticate my 3.8 engine block matches my Century (numbers matching). The flat pad on the left side of block where it mates to trans has no numbers stamped there. The raised cast numbers on top of the rear of engine block is 1261438 which I found to be a 1978 turbo. The engine block is pretty dirty so an area to know where look would be good. Did they stamp them in a different area for earlier turbo 3.8s? I did find my build sheet behind the door panel luckily. It shows Century Sport and Turbo Coupe. My cowl tag for sure reads
79 4AE87 Z 088847
24C AM6 22L 22U
11C 19B 660059
79 4AE87 Z 088847
24C AM6 22L 22U
11C 19B 660059