I am in agreement that the 289 block itself is the same, apart from the main caps. I believe the
oil galley plugs were screw in rather than press in. The freeze plugs are the standard fare press in type. You can convert them to screw in type (like the Boss 302). Also the bottoms of the cylinder bores are not as long as the 302 block and in a stroker application will not support the skirts of the pistons as well as the 302 block. There were a batch of 289 blocks cast which had 4 bolt mains, the block evolved into what became the Boss 302 block. A well built 289 is bullit proof!
Rick