Question about 360 blocks

Only partially true. '71 dated 360s have the thicker bore castings. All C body models that year could have had them. After 72, the 360 blocks used the 360 cylinder cores. All 360 blocks are viable for a 4" stroke with a .030 overbore. If you plan make big power, or want to go wit a bigger bore (larger than 4.03) then the bores should be sonic tested properly before you spend a dime on parts.