The 4.6 block is just a better built block. I don't remember if it's aluminum or not, although, it could change from year to year. I"m pretty sure it can just take more of a beating than our old 5.0's, just purely by design (500 to 600 hp limit?). I"m talking stock block now, obviously it would be better to have a 5.0 built up, but the 4.6, stock block for stock block, just had more design and can take more power.