Have pictures and will post this afternoon once I get home. It's in a 67-72 (don't know these trucks well, has quad headlights) GMC. Engine has a rebuild tag with a bunch of info on the build. Block is pretty much free of grease and grime. I've definitely got the number right.

Interesting.

1953 2dr 150 with '59 261
1964 Bel Air with stock ~69 230
1961 Biscayne with stuck 235
tore up '53 235