I recently put one on my World block, 4.5 bore. Easy installation but a few things we discovered. You will need longer bolts for the electric water pump as the Milodon spaces the water pump out to clear the cover. You will need a new dampner or a spacer behind the existing dampner along with longer bolts for mounting the dampner. Outside of these, I really like the Milodon and it is not very noisy at all.
