I never thought the 289/302/351 blocks are all windsor blocks, is this true? It doesn't make sense how people call only 351 the Windsor motor if the rest are all Windsor motors as well. Are Boss motors Windsors too? So confused...
Some of these answers are correct. The 351w is called a Windsor, because it was built at the Windsor plant. The Cleveland was built in the Cleveland plant. A 302/289 are the same block, just diff. cubic inches. They both share similar characteristics of the 351w, such as bore size, water passages, etc. That is why heads, timing covers, water pumps and other things swap over. The 302 was built at a different plant, but they are linked becuase of the fact that they are similar.
As said, they were called windsors because of the plants they were made at. It has nothing to do with similarities in construction.
The new modular motors are not all Clevelands. The DOHC motors are mostly Romeo's, while the SOHC's are mostly clevelands. almost all parts are interchangeable for the mod motors. In fact, there is only 1 head design for each engine. there is no leftand right, they are all the same just like the old pushrod motors.
A Boss 302 is a boss block (see avitar and note the screw in style casting cores...I know the pic is small and kind of crappy though) with Boss heads. The cleveland heads are fashoned after the Boss heads. The Boss heads also flow a little more than the clevaland heads.