Im just a dreamer : 440 vs 360 magnum

The small block weighs less, so that will also help out with some added performance. If you want the 440 to run really well you need to increase the compression and milling the heads isn't going to get enough to make it worth the trouble. Take it apart, deck the block .100" and put it back together is how I would do it on the cheap, or if you want to spend some money buy a set of pistons and bore it .030" over. Then you can get a 440 that will walk the dog over that 360.

Tom