I’ve got a bud who bought a 528 Arruza hemi. It was a pre world block. I’m not sure I remember the specs but I pretty sure it was a 4.25 bore originally. I think he went with a .100 over bore and a 4.25 crank. I’m too lazy to dig up a website and do the math but I think that was it. You can still use the internal oil pickup with a 4.25 stroke. He has no trouble with heat problems even in Texas. He has a roller cam that is way too big or he would drive it more often.