I am wondering if anyone knows of a sbc 400 block which is stronger than others. I am familiar with the 509, 511, and 817 blocks. I am only posting the last three digits. I think that the 350 #0100 block is always a 4 bolt main and if one looks under the timing chain cover, if you find 020 vs 010, then you have a higher nickle content block. Sooo, is there a higher nickle content factory 400 block not including the bowtie blocks.