aluminum block vs cast iron block

[John Wheatley]

I'm wondering if anyone has any real world examples of power differences between a good, high quality aluminum block as opposed to an equivalent cast iron block. I suspect the iron block will make more power, but I'm wondering how much.

[ALKYBURNER]

We have currently re built an engine that is blown alcohol small block chevy that the only thing that was changed was from a dart aluminum block to the cnc billet block and there was a good 8 thou more fuel added to the engine to get the plug readings the same as before 3 threads of heat on an ngk v power.