There's the question - Is the bellhousing flange bolt pattern on the Y-block the same as the Windsor 221/260/early 289? I know that the 221 and maybe the 260 date back far enough. I suppose that they (the 221/260) were the replacements for the passenger car applications of the Y-block, so the idea that the transmissions that bolted to the Y-block also bolt to the 221/260 and visa-versa.

 

I am sure the Y block bell housing had a different pattern than the small block V-8s had.