From what I remember even the 426 hemi heads would bolt to the other big blocks, but ( and this is going back 30 years so may NOT be 100%) had to have push rod clearance machined into the block.
The heads will almost bolt on (they fit any other "RB" block) HOWEVER there are 4 head bolt holes missing on the "RB" block accept, the HEMI block which has the bolt holes cast into them. (the extra head bolt holes are for extra clamping force I believe.
Someone at one point and time it seems sold a kit to bolt them to 440 blocks.