all 351w block are basically the same. no extra nickle was added, teh cranks were all cast, the only real difference was the deck height was changed from 9.48" to 9.503" in 1971(i think). the next change in deck height happened in like 1990 or so, and added like .020". otherwise any 351w block is a good base to build a healthy engine from.
all 351w block are basically the same. no extra nickle was added, teh cranks were all cast, the only real difference was the deck height was changed from 9.48" to 9.503" in 1971(i think). the next change in deck height happened in like 1990 or so, and added like .020". otherwise any 351w block is a good base to build a healthy engine from.
actually only the 69/70 blocks have a different deck height, the 71-97 blocks are all the same 9.503 deck height. the only blocks to really stay away from are the early 80's blocks like the E1 casting blocks.
EDIT: the 69-74 blocks have a little more meat in the main saddles but that doesn't really matter much unless you are doing a 4 bolt main conversion or are making more than 500hp