Everything else being the same, the larger cube engine would make the same power at a lower rpm point, so you wouldn't have to rev it as high. But with a bigger cylinder head, the game changes a little. Max flow on the -1's isn't relevant if you are still using the old cam that doesn't come anywhere near that amount of lift. You need to check the lift points within your cam lift. I don't really think there would be a drastic difference in engine operation with only a 15 inch increase in displacement, anyway. The bigger heads will be the game changer for you.