Actually, the 429/460 engines are 385 series as is the boss 429. The Y block is a totally different series again. Think 292 and 312 t bird engines. The SOHC " cammer" is based on an FE is 427 cubic inches The last performance FE engines were the 428 cobra jets
The boss 429 was not a true Hemi as it only had a semi hemispherical combustion chamber. Hope this helps. I digest Ford engine part numbers in my sleep and have had my hands on every one of the engines I listed ?